Sample records for thin film superconductor

  1. Thin film superconductor magnetic bearings

    DOEpatents

    Weinberger, Bernard R. (Avon, CT)

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  2. Thin film superconductors and process for making same

    DOEpatents

    Nigrey, P.J.

    1988-01-21

    A process for the preparation of oxide superconductors from high-viscosity non-aqueous solution is described. Solutions of lanthanide nitrates, alkaline earth nitrates and copper nitrates in a 1:2:3 stoichiometric ratio, when added to ethylene glycol containing citric acid solutions, have been used to prepare highly viscous non-aqueous solutions of metal mixed nitrates-citrates. Thin films of these compositions are produced when a layer of the viscous solution is formed on a substrate and subjected to thermal decomposition.

  3. Terahertz transmission of NbN superconductor thin film

    Microsoft Academic Search

    R. Tesar; J. Kolácek; Z. Šimša; M. Šindler; L. Skrbek; K. Il'in; M. Siegel

    2010-01-01

    Transmission of terahertz waves through a thin layer of the NbN superconductor deposited on a sapphire substrate was studied as a function of temperature in zero field as well as in magnetic field perpendicular to the sample. For photon energies lower than optical gap, detailed temperature measurements in zero field provide BCS-like curves with a pronounced peak below the critical

  4. Discriminator Stabilized Superconductor/Ferroelectric Thin Film Local Oscillator

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor); Miranda, Felix A. (Inventor)

    2000-01-01

    A tunable local oscillator with a tunable circuit that includes a resonator and a transistor as an active element for oscillation. Tuning of the circuit is achieved with an externally applied dc bias across coupled lines on the resonator. Preferably the resonator is a high temperature superconductor microstrip ring resonator with integral coupled lines formed over a thin film ferroelectric material. A directional coupler samples the output of the oscillator which is fed into a diplexer for determining whether the oscillator is performing at a desired frequency. The high-pass and lowpass outputs of the diplexer are connected to diodes respectively for inputting the sampled signals into a differential operational amplifier. The amplifier compares the sampled signals and emits an output signal if there is a difference between the resonant and crossover frequencies. Based on the sampled signal, a bias supplied to the ring resonator is either increased or decreased for raising or lowering the resonant frequency by decreasing or increasing, respectively, the dielectric constant of the ferroelectric.

  5. Pseudogap in a thin film of a conventional superconductor.

    SciTech Connect

    Sacepe, B.; Chapelier, C.; Baturina, T. I.; Vinokur, V. M.; Baklanov, M. R.; Sanquer, M. (Materials Science Division); (CEA-INAC/UJF-Grenoble); (A.V. Rzhanov Inst. Semiconductor Physics); (IMEC)

    2010-12-01

    A superconducting state is characterized by the gap in the electronic density of states, which vanishes at the superconducting transition temperature T{sub c}. It was discovered that in high-temperature superconductors, a noticeable depression in the density of states, the pseudogap, still remains even at temperatures above T{sub c}. Here, we show that a pseudogap exists in a conventional superconductor, ultrathin titanium nitride films, over a wide range of temperatures above T{sub c}. Our study reveals that this pseudogap state is induced by superconducting fluctuations and favoured by two-dimensionality and by the proximity to the transition to the insulating state. A general character of the observed phenomenon provides a powerful tool to discriminate between fluctuations as the origin of the pseudogap state and other contributions in the layered high-temperature superconductor compounds.

  6. Magnetoconductance of thin-film superconductors near critical disorder

    SciTech Connect

    Brenig, W.; Paalanen, M.A.; Hebard, A.F.; Woelfle, P.

    1986-02-01

    Gauge-invariant approximations are used to derive all diagrams for the current response function to lowest order in the superconducting pair fluctuations. The resulting expression for the magnetoconductance extends the range in temperature and magnetic field over which meaningful comparisons with experimental data can be made. This aspect of the theory is illustrated in an analysis of magnetoconductance data on 100-A-thick In/InO/sub x/ superconductors near critical disorder where the transition temperature is rapidly suppressed with increasing sheet resistance. The temperature dependence and magnitude of the derived inelastic scattering rate is in good agreement with theory which includes the effect of superconducting fluctuations on the two-dimensional inelastic electron-electron scattering rate.

  7. A Novel Method for Characterization of Superconductors: Physical Measurements and Modeling of Thin Films

    NASA Technical Reports Server (NTRS)

    Kim, B. F.; Moorjani, K.; Phillips, T. E.; Adrian, F. J.; Bohandy, J.; Dolecek, Q. E.

    1993-01-01

    A method for characterization of granular superconducting thin films has been developed which encompasses both the morphological state of the sample and its fabrication process parameters. The broad scope of this technique is due to the synergism between experimental measurements and their interpretation using numerical simulation. Two novel technologies form the substance of this system: the magnetically modulated resistance method for characterizing superconductors; and a powerful new computer peripheral, the Parallel Information Processor card, which provides enhanced computing capability for PC computers. This enhancement allows PC computers to operate at speeds approaching that of supercomputers. This makes atomic scale simulations possible on low cost machines. The present development of this system involves the integration of these two technologies using mesoscale simulations of thin film growth. A future stage of development will incorporate atomic scale modeling.

  8. Thin film growth of the 2122-phase of BCSCO superconductor with high degree of crystalline perfection

    NASA Technical Reports Server (NTRS)

    Raina, K. K.; Narayanan, S.; Pandey, R. K.

    1992-01-01

    Thin films of the 80 K-phase of BiCaSrCu-oxide superconductor having the composition of Bi2Ca1.05Sr2.1Cu2.19O(x) and high degree of crystalline perfection have been grown on c-axis oriented twin free single crystal substrates of NdGaO3. This has been achieved by carefully establishing the growth conditions of the LPE experiments. The temperature regime of 850 to 830 C and quenching of the specimens on the termination of the growth period are found to be pertinent for the growth of quasi-single crystalline superconducting BCSCO films on NdGaO3 substrates. The TEM analysis reveals a single crystalline nature of these films which exhibit 100 percent reflectivity in infrared regions at liquid nitrogen temperature.

  9. Nanopattern-stimulated superconductor-insulator transition in thin TiN films.

    SciTech Connect

    Baturina, T. I.; Vinokur, V. M.; Mironov, A. Yu.; Chtchelkatchev, N. M.; Nasimov, D. A.; Latyshev, A. V. (Materials Science Division); (A. V. Rzhanov Inst. Semoconductor Physics); (Russian Academy of Sciences)

    2011-02-01

    We present the results of the comparative study of transport properties of continuous and nanoperforated TiN films, enabling us to separate the disorder and the geometry effects. Nanopatterning transforms a thin TiN film into an array of superconducting weak links and eo ipso stimulates the disorder- and magnetic-field-driven superconductor-to-insulator transitions, shifting both transitions to a lower degree of microscopic disorder. We observe magnetoresistance oscillations reflecting collective phase-frustration behaviour of the multiconnected superconducting weak link network in a wide range of temperatures. We find that nanopatterning enhances the role of the two-dimensional Coulomb interaction and changes the characteristic energies of the film on length scales significantly larger than the mean free path or the superconducting coherence length.

  10. Optical properties of TiN thin films close to the superconductor-insulator transition

    NASA Astrophysics Data System (ADS)

    Pfuner, F.; Degiorgi, L.; Baturina, T. I.; Vinokur, V. M.; Baklanov, M. R.

    2009-11-01

    We present the intrinsic optical properties over a broad spectral range of TiN thin films deposited on an Si/SiO2 substrate. We analyze the measured reflectivity spectra of the film-substrate multilayer structure within a well-establish procedure based on the Fresnel equation and extract the real part of the optical conductivity of TiN. We identify the metallic contribution as well as the finite energy excitations and disentangle the spectral weight distribution among them. The absorption spectrum of TiN bears some similarities with the electrodynamic response observed in the normal state of the high-temperature superconductors. Particularly, a mid-infrared feature in the optical conductivity is quite reminiscent of a pseudogap-like excitation.

  11. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    NASA Astrophysics Data System (ADS)

    Singh, R.; Sinha, S.; Hsu, N. J.; Thakur, R. P. S.; Chou, P.; Kumar, A.; Narayan, J.

    1991-01-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectrics having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writing capability, complex device structures like three terminal hybrid semiconductor/superconductor transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray deffraction, electron microscopy, and energy dispersive x-ray analysis are discussed.

  12. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    NASA Astrophysics Data System (ADS)

    Singh, R.; Sinha, S.; Hsu, N. J.; Thakur, R. P. S.; Chou, P.; Kumar, A.; Narayan, J.

    1990-04-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid semiconductors/superconductors transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray defraction, electron microscopy, and energy dispersive x-ray analysis are discussed.

  13. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    NASA Technical Reports Server (NTRS)

    Singh, R.; Sinha, S.; Hsu, N. J.; Thakur, R. P. S.; Chou, P.; Kumar, A.; Narayan, J.

    1990-01-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid semiconductors/superconductors transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray defraction, electron microscopy, and energy dispersive x-ray analysis are discussed.

  14. Ion beam analysis and modification of thin-film, high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Nastasi, Michael

    1989-10-01

    The application of ion beams to ceramic processing is a very powerful technique. In particular, ion beams have been shown to be very effective in producing novel material properties through their rather violent interactions with the component atoms of the ceramics. However, in all these cases ions are used to process and produce changes in ceramics, changes that must be monitored by other techniques. This paper shows that, in addition to modifying materials, ion beams can be used in a more gentle but very powerful way to explore what happens to a ceramic thin film as a result of processing. The following discussions are concerned exclusively with a new and exciting class of ceramic: the high-temperature superconductor (HTS). We will discuss the application of various ion beam backscattering techniques as well as examine the use of ion implantation in the processing of these materials.

  15. Thin film growth of Fe-based superconductors: from fundamental properties to functional devices. A comparative review

    NASA Astrophysics Data System (ADS)

    Haindl, S.; Kidszun, M.; Oswald, S.; Hess, C.; Büchner, B.; Kölling, S.; Wilde, L.; Thersleff, T.; Yurchenko, V. V.; Jourdan, M.; Hiramatsu, H.; Hosono, H.

    2014-04-01

    Fe-based superconductors bridge a gap between MgB2 and the cuprate high temperature superconductors as they exhibit multiband character and transition temperatures up to around 55 K. Investigating Fe-based superconductors thus promises answers to fundamental questions concerning the Cooper pairing mechanism, competition between magnetic and superconducting phases, and a wide variety of electronic correlation effects. The question addressed in this review is, however, is this new class of superconductors also a promising candidate for technical applications? Superconducting film-based technologies range from high-current and high-field applications for energy production and storage to sensor development for communication and security issues and have to meet relevant needs of today's society and that of the future. In this review we will highlight and discuss selected key issues for Fe-based superconducting thin film applications. We initially focus our discussion on the understanding of physical properties and actual problems in film fabrication based on a comparison of different observations made in the last few years. Subsequently we address the potential for technological applications according to the current situation.

  16. Thin film growth of Fe-based superconductors: from fundamental properties to functional devices. A comparative review.

    PubMed

    Haindl, S; Kidszun, M; Oswald, S; Hess, C; Buchner, B; Kolling, S; Wilde, L; Thersleff, T; Yurchenko, V V; Jourdan, M; Hiramatsu, H; Hosono, H

    2014-04-01

    Fe-based superconductors bridge a gap between MgB2 and the cuprate high temperature superconductors as they exhibit multiband character and transition temperatures up to around 55 K. Investigating Fe-based superconductors thus promises answers to fundamental questions concerning the Cooper pairing mechanism, competition between magnetic and superconducting phases, and a wide variety of electronic correlation effects. The question addressed in this review is, however, is this new class of superconductors also a promising candidate for technical applications? Superconducting film-based technologies range from high-current and high-field applications for energy production and storage to sensor development for communication and security issues and have to meet relevant needs of today’s society and that of the future. In this review we will highlight and discuss selected key issues for Fe-based superconducting thin film applications. We initially focus our discussion on the understanding of physical properties and actual problems in film fabrication based on a comparison of different observations made in the last few years. Subsequently we address the potential for technological applications according to the current situation. PMID:24695004

  17. Electronically driven superconductor-insulator transition in electrostatically doped La2CuO4+? thin films

    NASA Astrophysics Data System (ADS)

    Garcia-Barriocanal, J.; Kobrinskii, A.; Leng, X.; Kinney, J.; Yang, B.; Snyder, S.; Goldman, A. M.

    2013-01-01

    Using an electronic double layer transistor we have systematically studied the superconductor-to-insulator transition in La2CuO4+? thin films grown by ozone-assisted molecular-beam epitaxy. We have confirmed the high crystalline quality of the cuprate films and have demonstrated the suitability of the electronic double layer technique to continuously vary the charge density in a system that is otherwise characterized by the presence of miscibility gaps. The transport and magnetotransport results highlight the role of electron-electron interactions in the mechanism of the transition due to the proximity of the Mott-insulating state.

  18. Fabrication of high T(sub c) superconductor thin film devices: Center director's discretionary fund

    NASA Technical Reports Server (NTRS)

    Sisk, R. C.

    1992-01-01

    This report describes a technique for fabricating superconducting weak link devices with micron-sized geometries etched in laser ablated Y1Ba2Cu3O(x) (YBCO) thin films. Careful placement of the weak link over naturally occurring grain boundaries exhibited in some YBCO thin films produces Superconducting Quantum Interference Devices (SQUID's) operating at 77 K.

  19. Epitaxial layers of 2122 BCSCO superconductor thin films having single crystalline structure

    NASA Technical Reports Server (NTRS)

    Pandey, Raghvendra K. (Inventor); Raina, Kanwal K. (Inventor); Solayappan, Narayanan (Inventor)

    1995-01-01

    A substantially single phase, single crystalline, highly epitaxial film of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor which has a T.sub.c (zero resistance) of 83K is provided on a lattice-matched substrate with no intergrowth. This film is produced by a Liquid Phase Epitaxy method which includes the steps of forming a dilute supercooled molten solution of a single phase superconducting mixture of oxides of Bi, Ca, Sr, and Cu having an atomic ratio of about 2:1:2:2 in a nonreactive flux such as KCl, introducing the substrate, e.g., NdGaO.sub.3, into the molten solution at 850.degree. C., cooling the solution from 850.degree. C. to 830.degree. C. to grow the film and rapidly cooling the substrate to room temperature to maintain the desired single phase, single crystalline film structure.

  20. Method for forming single phase, single crystalline 2122 BCSCO superconductor thin films by liquid phase epitaxy

    NASA Technical Reports Server (NTRS)

    Pandey, Raghvendra K. (Inventor); Raina, Kanwal (Inventor); Solayappan, Narayanan (Inventor)

    1994-01-01

    A substantially single phase, single crystalline, highly epitaxial film of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor which has a T.sub.c (zero resistance) of 83 K is provided on a lattice-matched substrate with no intergrowth. This film is produced by a Liquid Phase Epitaxy method which includes the steps of forming a dilute supercooled molten solution of a single phase superconducting mixture of oxides of Bi, Ca, Sr, and Cu having an atomic ratio of about 2:1:2:2 in a nonreactive flux such as KCl, introducing the substrate, e.g., NdGaO.sub.3, into the molten solution at 850.degree. C., cooling the solution from 850.degree. C. to 830.degree. C. to grow the film and rapidly cooling the substrate to room temperature to maintain the desired single phase, single crystalline film structure.

  1. Thin films of the Bi2Sr2Ca2Cu3O(x) superconductor

    NASA Technical Reports Server (NTRS)

    Mei, YU; Luo, H. L.; Hu, Roger

    1990-01-01

    Using RF sputtering technique, thin films of near single phase Bi2Sr2Ca2Cu3O(x) were successfully prepared on SrTiO3(100), MgO(100), and LaAlO3(012) substrates. Zero resistance of these films occurred in the range of 90-105 K.

  2. Ultra-thin film superconductors of artificially synthesized Au/Ge layers

    NASA Astrophysics Data System (ADS)

    Seguchi, Yasuhiro; Tsuboi, Takefumi; Suzuki, Takao

    1990-08-01

    We have investigated the resistive transition of Au/Ge layered films. The ultra-thin bilayer of Au(10?)/Ge(13?) exhibits superconductivi ty below a temperature of 0.6 K. It has been found thatthe critical temperature T C is enhanced above T C0 by the application of low magnetic field parallel to the film surface. We have observed dimensional crossover in the temperature dependence of parallel critical field for the multilayers with Ge film ~25 ? thick. Those with Ge film thicker than ~30 ? show two-dimensional behavior and also the T C enhancement as observed in the bilayer.

  3. MOCVD approach to perovskite based thin films: From high Tc superconductors to giant dielectric constant materials

    NASA Astrophysics Data System (ADS)

    Malandrino, G.; Toro, R. G.; Lo Nigro, R.; Fragalà, I. L.

    2010-02-01

    Perovskite thin films with various functional properties have been synthesized through the Metal Organic Chemical Vapour Deposition (MOCVD). The MOCVD processes, used for the fabrication of a variety of advanced materials in thin film form, rely upon application of a molten multi-element source. The challenging in-situ strategy involves the use of a molten source consisting of a second-generation M(hfa)n•polyether (M = La, Ca, and Y; polyether = diglyme or tetraglyme) precursor which acts as a solvent for the other species. The approach is reported as a general route to the fabrication of multi-element oxides.

  4. Thin film seeds for melt processing textured superconductors for practical applications

    DOEpatents

    Veal, B.W.; Paulikas, A.; Balachandran, U.; Zhong, W.

    1999-02-09

    A method of fabricating bulk superconducting material such as RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} where R is La or Y comprising depositing a thin epitaxially oriented film of Nd or Sm (123) on an oxide substrate is disclosed. The powder oxides of RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} or oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}, where R is Y or La are heated, in physical contact with the thin film of Nd or Sm (123) on the oxide substrate to a temperature sufficient to form a liquid phase in the oxide or carbonate mixture while maintaining the thin film solid to grow a large single domain 123 superconducting material. Then the material is cooled. The thin film is between 200 {angstrom} and 2000 {angstrom}. A construction prepared by the method is also disclosed.

  5. Thin film seeds for melt processing textured superconductors for practical applications

    DOEpatents

    Veal, Boyd W. (Downers Grove, IL); Paulikas, Arvydas (Downers Grove, IL); Balachandran, Uthamalingam (Hinsdale, IL); Zhong, Wei (West Lafayette, IN)

    1999-01-01

    A method of fabricating bulk superconducting material such as RBa.sub.2 Cu.sub.3 O.sub.7-.delta. where R is La or Y comprising depositing a thin epitaxially oriented film of Nd or Sm (123) on an oxide substrate. The powder oxides of RBa.sub.2 Cu.sub.3 O.sub.7-.delta. or oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa.sub.2 Cu.sub.3 O.sub.7-.delta., where R is Y or La are heated, in physical contact with the thin film of Nd or Sm (123) on the oxide substrate to a temperature sufficient to form a liquid phase in the oxide or carbonate mixture while maintaining the thin film solid to grow a large single domain 123 superconducting material. Then the material is cooled. The thin film is between 200 .ANG. and 2000 .ANG.. A construction prepared by the method is also disclosed.

  6. atomic layer deposition of amorphous niobium carbide-based thin film superconductors.

    SciTech Connect

    Prolier, T.; Klug, J. A.; Elam, J. W.; Claus, H.; Becker, N. G.; Pellin, M. J. (Materials Science Division)

    2011-01-01

    Niobium carbide thin films were synthesized by atomic layer deposition (ALD) using trimethylaluminum (TMA), NbF{sub 5}, and NbCl{sub 5} precursors. In situ quartz crystal microbalance (QCM) measurements performed at 200 and 290 C revealed controlled, linear deposition with a high growth rate of 5.7 and 4.5 {angstrom}/cycle, respectively. The chemical composition, growth rate, structure, and electronic properties of the films were studied over the deposition temperature range 125-350 C. Varying amounts of impurities, including amorphous carbon (a-C), AlF{sub 3}, NbF{sub x}, and NbCl{sub x}, were found in all samples. A strong growth temperature dependence of film composition, growth rate, and room temperature DC resistivity was observed. Increasing film density, decreasing total impurity concentration, and decreasing resistivity were observed as a function of increasing deposition temperature for films grown with either NbF{sub 5} or NbCl{sub 5}. Superconducting quantum interference device (SQUID) magnetometry measurements down to 1.2 K revealed a superconducting transition at T{sub c} = 1.8 K in a 75 nm thick film grown at 350 C with TMA and NbF{sub 5}. The superconducting critical temperature could be increased up to 3.8 K with additional use of NH{sub 3} during ALD film growth.

  7. Atomic layer deposition of amorphous niobium carbide-based thin film superconductors.

    SciTech Connect

    Klug, J. A.; Prolier, T.; Elam, J. W.; Becker, N. G.; Pellin, M. J. (Energy Systems); ( HEP); ( MSD); (Illinois Inst. Tech.)

    2011-01-01

    Niobium carbide thin films were synthesized by atomic layer deposition (ALD) using trimethylaluminum (TMA), NbF{sub 5}, and NbCl{sub 5} precursors. In situ quartz crystal microbalance (QCM) measurements performed at 200 and 290 C revealed controlled, linear deposition with a high growth rate of 5.7 and 4.5 {angstrom}/cycle, respectively. The chemical composition, growth rate, structure, and electronic properties of the films were studied over the deposition temperature range 125-350 C. Varying amounts of impurities, including amorphous carbon (a-C), AlF{sub 3}, NbF{sub x}, and NbCl{sub x}, were found in all samples. A strong growth temperature dependence of film composition, growth rate, and room temperature DC resistivity was observed. Increasing film density, decreasing total impurity concentration, and decreasing resistivity were observed as a function of increasing deposition temperature for films grown with either NbF{sub 5} or NbCl{sub 5}. Superconducting quantum interference device (SQUID) magnetometry measurements down to 1.2 K revealed a superconducting transition at T{sub c} = 1.8 K in a 75 nm thick film grown at 350 C with TMA and NbF{sub 5}. The superconducting critical temperature could be increased up to 3.8 K with additional use of NH{sub 3} during ALD film growth.

  8. Thin Films

    NASA Astrophysics Data System (ADS)

    Bagade, A. A.; Ganbavle, V. V.; Rajpure, K. Y.

    2014-08-01

    Cobalt ferrite thin films are deposited onto quartz glass substrates by chemical spray pyrolysis technique at different substrate temperatures using ferric nitrate and cobalt nitrate as precursors. Thermogravimetric analysis (TGA) study indicates the formation of CoFe2O4 by decomposition of cobalt and ferric nitrates after 800 °C. X-ray diffraction studies reveal that annealed films are polycrystalline in nature and exhibit spinel cubic crystal structure. Crystallite size varies from 39 to 44 nm with the substrate temperatures. Direct optical band gap energy of CoFe2O4 thin films is found to be 2.57 eV. The AFM images show that roughness and grain size of the CoFe2O4 thin film are about 9 and 138 nm, respectively. The measured DC resistivity of the deposited thin films indicates that as temperature increases the resistivity decreases indicating the semiconductor nature of the films. Decrease in dielectric constant (?') and loss tangent (tan?) has been observed with frequency and attains the constant value at higher frequencies. The AC conductivity of cobalt ferrite thin films increases with increase in frequency. Thus, the prepared films show normal dielectric performance of the spinel ferrite thin film. Room-temperature complex impedance spectra show the incomplete semicircles as films exhibit high resistance values at lower frequencies.

  9. Melt process of Sm-Ba-Cu-O bulk superconductors by thin film cold seeding

    NASA Astrophysics Data System (ADS)

    Fujimoto, H.; Ozaku, H.; Ohtabara, E.

    2003-10-01

    We discuss Sm123 bulks melt-processed in air and their characteristic superconducting properties for improving superconducting properties and producing a larger bulk. Isothermal undercooling growth in air with oxygen annealing and Nd123/MgO thin film cold seeding technique were applied in SmBaCuOy/Ag system to seek the high-efficiency of process, homogeneity of composition, and feasibility of batch production. We investigated process conditions such as heat treatment temperatures, compositions, seeding methods, and atmosphere. Single-domain growth of superconducting phases of a square larger than 10 mm on a side and 5 mm in thickness was achieved using this technique. Tc,onset and Tc,zero are 94 and 90 K, and Jc is 3 × 10 4 A/cm 2 at around 2 T at 77 K with a typical peak effect in the LRE system. In the case of Sm211 = 10 and 40 mol% addition, the maximum trapped magnetic field of the bulks is 1000 and 2100 G, respectively. The maximum magnetic field increases as Sm211 volume fractions increase. The result implies that melt-processed in air applying isothermal method and thin film seeding in Sm system is feasible for producing larger bulks in large scale applications.

  10. Superconductivity in Thin Films of the Heavy Fermion Superconductors, URANIUM-PLATINUM(3) and URANIUM-BERYLLIUM(13)

    NASA Astrophysics Data System (ADS)

    Kang, Joonhee

    Thin films of the heavy fermion superconductors, UBe_{13} and UPt _3 have been fabricated by dc sputtering. The growth of superconducting UBe_{13} films was easier than that of UPt_3 films because of much lower preparation temperature. Superconducting properties of UBe_{13} films were very similar to those of UBe_ {13} bulk material. Even though X-ray diffraction analysis showed that well ordered UPt _3 films had been prepared, the superconducting properties of the UPt_3 films were poor because of the presence of small concentrations of impurity phases. Impurity phase formation was difficult to deal with because temperatures as high as 1200 ^circC were required in the processing and because of the great sensitivity of UPt_3 to impurities. A difference between UBe _{13} films and bulk materials is the absence of the resistance peak at 2.4 K observed in bulk material in the films, a result which suggests that the resistance peak is unrelated to superconductivity. This is in contrast with a common view that it is. However the broad maximum in the normal state resistance found near 20 K was observed. The temperature dependence of the parallel and perpendicular critical magnetic fields of UBe_{13} films have been measured. The ratio of the critical fields, H _{{rm c2}parallel} /H_{{rm c2} |}, has been found to be at least 1.25 over the whole temperature range below T_ {rm c}, a value less than would be expected for s-wave pairing without surface pair-breaking, but greater than expected for any pairing configuration which is a pure angular momentum state with L not= 0. This observation suggests the existence of s-wave superconductivity in UBe_{13 } at least near its surfaces. A proximity effect experiment has been carried on UBe_ {13}/Al sandwiches. The measurement of critical fields of the Al layer suggests that there is no negative proximity effect between UBe_ {13} and Al, but rather positive proximity effect. This observation supports the view of the existence of s-wave superconductivity in UBe_{13 } which was drawn from the measurement of the surface superconductivity.

  11. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    Microsoft Academic Search

    R. Singh; S. Sinha; N. J. Hsu; R. P. S. Thakur; P. Chou; A. Kumar; J. Narayan

    1991-01-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectrics having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writing capability, complex device structures like three terminal

  12. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    Microsoft Academic Search

    R. Singh; S. Sinha; N. J. Hsu; R. P. S. Thakur; P. Chou; A. Kumar; J. Narayan

    1990-01-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid

  13. Epitaxial thin films

    DOEpatents

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  14. Thin Film?

    NASA Astrophysics Data System (ADS)

    Kariper, ?. Af?in

    2014-09-01

    This study focuses on the critical surface tension of lead sulfite (PbSO3) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO3 thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO3 thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.

  15. Thin Films

    NASA Astrophysics Data System (ADS)

    Khorshidi, Zahra; Bahari, Ali; Gholipur, Reza

    2014-11-01

    Effect of annealing temperature on the characteristics of sol-gel-driven Ta ax La(1- a) x O y thin film spin-coated on Si substrate as a high- k gate dielectric was studied. Ta ax La(1- a) x O y thin films with different amounts of a were prepared (as-prepared samples). X-ray diffraction measurements of the as-prepared samples indicated that Ta0.3 x La0.7 x Oy film had an amorphous structure. Therefore, Ta0.3 x La0.7 x O y film was chosen to continue the present studies. The morphology of Ta0.3 x La0.7 x O y films was studied using scanning electron microscopy and atomic force microscopy techniques. The obtained results showed that the size of grain boundaries on Ta0.3 x La0.7 x O y film surfaces was increased with increasing annealing temperature. Electrical and optical characterizations of the as-prepared and annealed films were investigated as a function of annealing temperature using capacitance-voltage ( C- V) and current density-voltage ( J- V) measurements and the Tauc method. The obtained results demonstrated that Ta0.3 x La0.7 x O y films had high dielectric constant (?27), wide band gap (?4.5 eV), and low leakage current density (?10-6 A/cm2 at 1 V).

  16. Ferromagnetic SrRuO3 thin-film deposition on a spin-triplet superconductor Sr2RuO4 with a highly conducting interface

    NASA Astrophysics Data System (ADS)

    Anwar, M. S.; Shin, Yeong Jae; Lee, Seung Ran; Kang, Sung Jin; Sugimoto, Yuske; Yonezawa, Shingo; Noh, Tae Won; Maeno, Yoshiteru

    2015-01-01

    Ferromagnetic SrRuO3 thin films are deposited on the ab surface of single crystals of the spin-triplet superconductor (TSC) Sr2RuO4 as substrates using pulsed laser deposition. The films are under a severe in-plane compressive strain. Nevertheless, the films exhibit ferromagnetic order with the easy axis along the c-direction below the Curie temperature of 158 K. The electrical transport reveals that the SrRuO3/Sr2RuO4 interface is highly conducting, in contrast with the interface between other normal metals and the ab surface of Sr2RuO4. Our results stimulate investigations on proximity effects between a ferromagnet and a TSC.

  17. 5. SUPERCONDUCTOR-METAL-INSULATOR TRANSITIONS: Vortex states at low temperature in disordered thin and thick films of a-MoxSi1-x

    NASA Astrophysics Data System (ADS)

    Okuma, S.; Morita, M.

    2001-10-01

    We have measured the ac complex resistivity in the linear regime, as well as dc resistivity, for thick (100, 300 nm) amorphous (a-)MoxSi1-x films at low temperatures (T > 0.04 K) in constant fields B. The critical behavior associated with the second-order transition has been observed for both dc and ac resistivities, which is similar to that observed for granular indium films. This is the first convincing evidence for the vortex glass transition (VGT) in the homogeneously disordered low-TC superconductors containing microscopic pinning centers. We have found that the VGT persists down to T ~ 0.1TC0 up to B ~ 0.9BC2(0), where TC0 and BC2(0) are the mean-field transition temperature and upper critical field at T = 0, respectively. At T ? 0 the VGT line Bg(T) extrapolates to a field below BC2(0), indicative of the presence of a T = 0 quantum-vortex-liquid phase in the region Bg(0) < B < BC2(0). For thin (4 nm) films the (T = 0) field-driven superconductor-insulator transition takes place at BC. We have not obtained evidence of the metallic quantum liquid phase below BC, while in B > BC an anomalous negative magnetoresistance (MR) suggesting the presence of the localized Cooper pairs has been observed. The negative MRis commonly observed for thin films; however, for thick films the MR is always positive. This means that the two-dimensionality plays an important role in the appearance of the negative MR (or localized Cooper pairs). The negative MR is no longer visible as the field is applied parallel to the film surface, consistent with the view that mobile vortices, as well as localized Cooper pairs, are present in B > BC.

  18. Thin Films

    NASA Astrophysics Data System (ADS)

    Naffouti, Wafa; Nasr, Tarek Ben; Mehdi, Ahmed; Kamoun-Turki, Najoua

    2014-11-01

    Titanium dioxide (TiO2) thin films were synthesized on glass substrates by spray pyrolysis. The effect of solution flow rate on the physical properties of the films was investigated by use of x-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy (AFM), and spectrophotometry techniques. XRD analysis revealed the tetragonal anatase phase of TiO2 with highly preferred (101) orientation. AFM images showed that grain size on top of TiO2 thin films depended on solution flow rate. An indirect band gap energy of 3.46 eV was determined by means of transmission and reflection measurements. The envelope method, based on the optical transmission spectrum, was used to determine film thickness and optical constants, for example real and imaginary parts of the dielectric constant, refractive index, and extinction coefficient. Ultraviolet and visible photoluminescence emission peaks were observed at room temperature. These peaks were attributed to the intrinsic emission and to the surface defect states, respectively.

  19. Proximity effects at the interface of a superconductor and a topological insulator in NbN-Bi2Se3 thin film bilayers

    NASA Astrophysics Data System (ADS)

    Koren, Gad

    2015-02-01

    In a search for a simple proximity system of a topological insulator and a superconductor for studying the role of surface versus bulk effects by gating, we report here on a first step toward this goal, namely the choice of such a system and its characterization. We chose to work with thin film bilayers of grainy 5 nm thick NbN films as the superconductor, overlayed with 20 nm thick topological layer of B{{i}2}S{{e}3} and compare the transport results to those obtained on a 5 nm thick reference NbN film on the same wafer. Bilayers with ex situ and in situ prepared NbN-B{{i}2}S{{e}3} interfaces were studied and two kinds of proximity effects were found. At high temperatures just below the superconducting transition, all bilayers showed a conventional proximity effect where the topological B{{i}2}S{{e}3} suppresses the onset or mid-transition Tc of the superconducting NbN films by about 1 K. At low temperatures, a cross-over of the resistance versus temperature curves of the bilayer and reference NbN film occurs, where the bilayers show enhancement of {{T}c}(R=0), Ic (the supercurrent) and the Andreev conductance, as compared to the bare NbN films. This indicates that superconductivity is induced in the B{{i}2}S{{e}3} layer at the interface region in between the NbN grains. Thus an inverse proximity effect in the topological material is demonstrated.

  20. Techniques for Connecting Superconducting Thin Films

    NASA Technical Reports Server (NTRS)

    Mester, John; Gwo, Dz-Hung

    2006-01-01

    Several improved techniques for connecting superconducting thin films on substrates have been developed. The techniques afford some versatility for tailoring the electronic and mechanical characteristics of junctions between superconductors in experimental electronic devices. The techniques are particularly useful for making superconducting or alternatively normally conductive junctions (e.g., Josephson junctions) between patterned superconducting thin films in order to exploit electron quantum-tunneling effects. The techniques are applicable to both low-Tc and high-Tc superconductors (where Tc represents the superconducting- transition temperature of a given material), offering different advantages for each. Most low-Tc superconductors are metallic, and heretofore, connections among them have been made by spot welding. Most high-Tc superconductors are nonmetallic and cannot be spot welded. These techniques offer alternatives to spot welding of most low-Tc superconductors and additional solutions to problems of connecting most high-Tc superconductors.

  1. Thin Film Technology: Adhesion in Thin Films

    SciTech Connect

    Martin, Peter M.

    2004-02-01

    Last month I addressed the subject of pinholes in thin films and ways to minimize them. The subject this month is another cause for success, or failure, of thin films, adhesion. I was motivated to discuss this horrendously complicated subject by a conference I recently attended, Adhesion Aspects of Thin Films (Orlando, December 15-17). This conference, organized by Dr.'s K.L. Mittal and R.H. Lacombe, was both stimulating and informative.

  2. Pyrolyzed thin film carbon

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  3. Absence of a Proximity Effect for a Thin-Films of a Bi2Se3 Topological Insulator Grown on Top of a Bi2Sr2CaCu2O8+? Cuprate Superconductor

    NASA Astrophysics Data System (ADS)

    Yilmaz, T.; Pletikosi?, I.; Weber, A. P.; Sadowski, J. T.; Gu, G. D.; Caruso, A. N.; Sinkovic, B.; Valla, T.

    2014-08-01

    Proximity-induced superconductivity in a 3D topological insulator represents a new avenue for observing zero-energy Majorana fermions inside vortex cores. Relatively small gaps and low transition temperatures of conventional s-wave superconductors put hard constraints on these experiments. Significantly larger gaps and higher transition temperatures in cuprate superconductors might be an attractive alternative to considerably relax these constraints, but it is not clear whether the proximity effect would be effective in heterostructures involving cuprates and topological insulators. Here, we present angle-resolved photoemission studies of thin Bi2Se3 films grown in situ on optimally doped Bi2Sr2CaCu2O8+? substrates that show the absence of proximity-induced gaps on the surfaces of Bi2Se3 films as thin as a 1.5 quintuple layer. These results suggest that the superconducting proximity effect between a cuprate superconductor and a topological insulator is strongly suppressed, likely due to a very short coherence length along the c axis, incompatible crystal and pairing symmetries at the interface, small size of the topological surface state's Fermi surface, and adverse effects of a strong spin-orbit coupling in the topological material.

  4. Absence of a proximity effect for a thin-films of a Bi2Se3 topological insulator grown on top of a Bi2Sr2CaCu2O(8+?) cuprate superconductor.

    PubMed

    Yilmaz, T; Pletikosi?, I; Weber, A P; Sadowski, J T; Gu, G D; Caruso, A N; Sinkovic, B; Valla, T

    2014-08-01

    Proximity-induced superconductivity in a 3D topological insulator represents a new avenue for observing zero-energy Majorana fermions inside vortex cores. Relatively small gaps and low transition temperatures of conventional s-wave superconductors put hard constraints on these experiments. Significantly larger gaps and higher transition temperatures in cuprate superconductors might be an attractive alternative to considerably relax these constraints, but it is not clear whether the proximity effect would be effective in heterostructures involving cuprates and topological insulators. Here, we present angle-resolved photoemission studies of thin Bi(2)Se(3) films grown in situ on optimally doped Bi(2)Sr(2)CaCu(2)O(8+?) substrates that show the absence of proximity-induced gaps on the surfaces of Bi(2)Se(3) films as thin as a 1.5 quintuple layer. These results suggest that the superconducting proximity effect between a cuprate superconductor and a topological insulator is strongly suppressed, likely due to a very short coherence length along the c axis, incompatible crystal and pairing symmetries at the interface, small size of the topological surface state's Fermi surface, and adverse effects of a strong spin-orbit coupling in the topological material. PMID:25148345

  5. The environmental degradation mechanism and protective organic thin film coatings on a high-temperature bismuth-cuprate superconductor

    NASA Astrophysics Data System (ADS)

    Lee, Donghun; Condrate, R. A., Sr.; Taylor, J. A.

    2001-02-01

    The degradation mechanism for Bi 2Sr 2CaCu 2O x (Bi-2212) in a highly humid air has been investigated. Using diffuse reflectance infrared Fourier transform spectroscopy, different reaction steps for carbonate formation with aging time were found to occur on the surface of the superconductors. During the initial stage, the calcium carbonate species mainly formed due to the preferred hydration of calcium ions because of their lower ionic-dipole interaction energy. At a later stage, the strontium carbonate species became the more dominant species because of the kinetics of this step along with the higher molar ratio of Sr 2+ to Ca 2+. In addition to the carbonates, larger amounts of Sr(OH) 2 · nH 2O ( n=1 or 8) and CuBi 2O 4, along with relatively small amounts of Ca(OH) 2 were also found on the surface along with Sr(OH) 2. The formation of larger amounts of strontium-related degradation products also led to larger amounts of Bi 2CuO 4 being formed. The effect of stearic acid coating on the degradation of the superconductor was also investigated with respect to long term durability in a very humid atmosphere. These coatings strongly prevented the formation of carbonates on the surface of (Bi,Pb) 2Sr 2Ca 2Cu 3O y (Bi,Pb-2223). Strong complex bonds between the carboxylate groups of the organic acids and the metal ions on the surface of the superconductor were formed, which helped to retard the degradation process for the superconducting phase.

  6. Investigation into the growth and structure of thin-film solid solutions of iron-based superconductors in the FeSe{sub 0.92}-FeSe{sub 0.5}Te{sub 0.5} system

    SciTech Connect

    Stepantsov, E. A., E-mail: stepantsov@ns.cryst.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Kazakov, S. M.; Belikov, V. V. [Moscow State University (Russian Federation)] [Moscow State University (Russian Federation); Makarova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Arpaia, R.; Gunnarsson, R.; Lombardi, F. [Chalmers University of Technology, Department of Microtechnology and Nanoscience (Sweden)] [Chalmers University of Technology, Department of Microtechnology and Nanoscience (Sweden)

    2013-09-15

    Thin films of FeSe{sub 0.92} and FeSe{sub 0.5}Te{sub 0.5} iron chalcogenide superconductors and solid solutions containing these components in different ratios have been grown on the surface of LaAlO{sub 3} (10 1-bar 2) crystals by pulsed laser deposition. Films of solid solutions have been deposited by simultaneous laser ablation from two targets of the FeSe{sub 0.92} and FeSe{sub 0.5}Te{sub 0.5} stoichiometric compositions onto one substrate. An X-ray diffraction study of the film structure shows that the films grown are epitaxial and their lattice parameters regularly vary with the ratio of the deposited components, which was controllably varied by changing the ablation intensities from the targets.

  7. Ceramic Composite Thin Films

    NASA Technical Reports Server (NTRS)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  8. Quasiparticle generation efficiency in superconducting thin films

    NASA Astrophysics Data System (ADS)

    Guruswamy, T.; Goldie, D. J.; Withington, S.

    2014-05-01

    Thin-film superconductors with thickness ˜30-500 nm are used as non-equilibrium quantum detectors for photons, phonons or more exotic particles. One of the most basic questions in determining their limiting sensitivity is the efficiency with which the quanta of interest couple to the detected quasiparticles. As low temperature superconducting resonators, thin films are attractive candidates for producing quantum-sensitive arrayable sensors and the readout uses an additional microwave probe. We have calculated the quasiparticle generation efficiency ?s for low energy photons in a representative, clean thin-film superconductor (Al) operating well below its superconducting transition temperature as a function of film thickness, within the framework of the coupled kinetic equations described by Chang and Scalapino (1978 J. Low Temp. Phys. 31 1-32). We have also included the effect of a lower frequency probe. We show that phonon loss from the thin film reduces ?s by as much as 40% compared to earlier models that considered relatively thick films or infinite volumes. We also show that the presence of the probe and signal enhances the generation efficiency slightly. We conclude that the ultimate limiting noise equivalent power of this class of detector is determined by the thin-film geometry.

  9. Characteristics of all-MgB2 superconductor insulator superconductor junctions obtained with as-grown MgB2 thin films

    NASA Astrophysics Data System (ADS)

    Shimakage, Hisashi; Wang, Zhen

    2006-05-01

    All-MgB2 SIS junctions were fabricated on c-plane sapphire substrates using AlN film for the insulator layer. The critical temperature of the lower MgB2 layer after the SIS junction fabrication process was 29 K, which remained the same as that of bare MgB2 films. On the other hand, the critical temperature of the upper MgB2 layer was depressed to 17 K. The current-voltage characteristics showed typical SIS properties with very clear tunnelling currents and gap voltages, demonstrating an excellent insulator covering of the lower MgB2 films. The Josephson current decreased exponentially with increasing AlN insulator layer thickness, and a Josephson current of 115 A cm-2 was obtained for the junction with a 0.14 nm thick AlN insulator. However, the Josephson currents of MgB2/AlN/MgB2 junctions were lower than that of MgB2/AlN/NbN junctions with the same AlN thickness; this indicated the existence of other insulator layers. The ideal modulation of Josephson current was observed by applying an external magnetic field; this indicated a uniform tunnelling current flow in the junctions. The gap voltages were investigated on the basis of the current-voltage characteristics.

  10. Thin Films Module

    NSDL National Science Digital Library

    This page from Nano-Link contains the document required for the thin films module. The activity requires a background in eight grade science. This 9 page guide includes background information on thin film interference, a hands-on learning activity, links to multimedia resources, and further readings. Visitors must complete a quick and free registration to access the materials.

  11. Studies of Solution Deposited Cerium Oxide Thin Films on Textured Ni-Alloy Substractes for YBCO Superconductor

    SciTech Connect

    Stewart, Erin L [ORNL; Bhuiyan, Md S [ORNL; Sathyamurthy, Srivatsan [ORNL; Paranthaman, Mariappan Parans [ORNL

    2006-01-01

    Cerium oxide (CeO2) buffer layers play an important role for the development of YBa2Cu3O7-x (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO2 films on textured Ni-3 a 4% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H2 gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 degrees C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO2 films. Highly textured CeO2 layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a Jc of 1.5 MA/cm2 were obtained on cerium acetylacetonate-based CeO2 films with sputtered YSZ and CeO2 cap layers.

  12. Critical issues in thin film microstructure development

    NASA Astrophysics Data System (ADS)

    Singh, R. K.; Rajan, K.

    1994-09-01

    Physical vapor deposition techniques are presently being used to deposit elemental thin films or multicomponent thin films of novel materials like superconductors, oxides, dielectrics, etc. The microstructure development of these films, especially grain growth processes are particularly important for optimization of their electrical properties. In this paper, we focus on two critical issues related to microstructural evolution in thin films: (i) modeling of microstructural evolution during vapor deposition, and (ii) anisotropic grain growth during post deposition annealing in non-cubic systems. One of the key issues in non-cubic oxide systems, especially in high-Tc superconductors, is the anisotropic nature of growth which gives rise to oriented films on lattice mismatched or amorphous substrates. The factors affecting grain growth in non-cubic systems which lead to textured film are discussed in detail. An overview is also presented on the new developments in the modeling of materials synthesis by physical vapor deposition techniques. It is suggested that there is a strong need to formulate theoretical and computational methodologies which bridge both continuum and atomistic descriptions. The concept of “closed” and “open” thermodynamic systems to classify a broad range of microstructural evolution issues in the deposition of thin films is introduced.

  13. Nanostructured polymer thin films

    NASA Astrophysics Data System (ADS)

    Shin, Kwanwoo

    2000-12-01

    Interfacial structures of polymer thin films in nanometer scale have been investigated. Various types of polymer thin films, i.e. thin films on a solid substrate, bilayer systems, a polymer thin film standing without any substrate, self-assembled polymer thin films including Langmuir ultrathin films and Langmuir-Blodgett films, and polyelectrolyte thin films in various solvents and thin films under high pressured CO2 are described and characterized by a number of modern characterization tools. The thickness of the oxide layer of Si wafers as a function of annealing temperature following treatment with either a modified Shiraki method or HF stripping have been measured. In both cases there exists a well defined oxide layer, approximately 20 A thick. The activation energies, obtained 31.6 and 19.3 kJ/mol for the hydrophilic and hydrophobic surfaces are consistent with the evaporation energy of water. X-ray specular (XR) and off-specular measurements of free standing polystyrene thin films as a function of molecular weight and thickness performed have been performed. Films thicker than a few radii of gyration (Rg) are well fit by a simple liquid model. The simple liquid model was found to be insufficient to fit the transverse diffuse data for films thinner than a few Rg. Combined x-ray and neutron reflectivity (NR) studies of PS-P4VP/R+X-(X = Br or I) polyelectrolytes show that even though the polyelectrolyte block is water soluble it remains adsorbed to the water surface. NR to measure the concentration profiles of sulfonated Polystyrene films with three different degrees of sulfonation in water, CCl4, and mixture of the two solvents have been used. The data show that, except for the x = 3.4% films where CCl4 is a good solvent, the largest degree of swelling occurred in the mixed solvent. In situ NR of d-PS thin films in CO2 at P < 700 bar were reported. A large swelling maximum occurs only at the supercritical/gas phase boundary. I introduce a new analysis method of XR using Fourier transformation with advantage of higher qz range and better resolution than those of neutron scattering can be applied for the "smaller contrast" interface.

  14. Thin Film Growth

    NSDL National Science Digital Library

    Rack, Philip D.

    This is a PDF version of lecture slides that discuss thin film growth processes. Slide topics include plasma properties, DC glow discharge, ionization, plasma species, magnetrons, collisions, and chemical reactions. Numerous charts and mathematical formulas are presented.

  15. Simulated Thin-Film Growth and Imaging

    NASA Astrophysics Data System (ADS)

    Schillaci, Michael

    2001-06-01

    Thin-films have become the cornerstone of the electronics, telecommunications, and broadband markets. A list of potential products includes: computer boards and chips, satellites, cell phones, fuel cells, superconductors, flat panel displays, optical waveguides, building and automotive windows, food and beverage plastic containers, metal foils, pipe plating, vision ware, manufacturing equipment and turbine engines. For all of these reasons a basic understanding of the physical processes involved in both growing and imaging thin-films can provide a wonderful research project for advanced undergraduate and first-year graduate students. After producing rudimentary two- and three-dimensional thin-film models incorporating ballsitic deposition and nearest neighbor Coulomb-type interactions, the QM tunneling equations are used to produce simulated scanning tunneling microscope (SSTM) images of the films. A discussion of computational platforms, languages, and software packages that may be used to accomplish similar results is also given.

  16. Exploring Materials: Thin Films

    NSDL National Science Digital Library

    Nanoscale Informal Science Education Network

    2010-01-01

    In this activity, learners create a colorful bookmark using a super thin layer of nail polish on water. Learners discover that a thin film creates iridescent, rainbow colors. This is a very fun and engaging activity for learners, and a great way to talk about how nanoscale structures often affect a materials' properties. SAFETY: Do this activity in a well-ventilated area.

  17. Magnetite thin films

    Microsoft Academic Search

    J. Feng; C. Bajorek; M.-A. Nicolet

    1972-01-01

    A low temperature process for converting hematite (?-Fe2O3) thin films into magnetite (Fe3O4is described. The films produced are unambiguously identified as magnetite by several complementary methods of analysis. These include ?-backscattering spectrography, X-ray powder diffractometry, and observations of electrical, magnetic, and optical properties.

  18. Thin film temperature sensor

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Przybyszewski, J. S.

    1980-01-01

    Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

  19. Thin film ceramic thermocouples

    NASA Technical Reports Server (NTRS)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  20. Thin film photovoltaic device

    DOEpatents

    Catalano, Anthony W. (Wilmington, DE); Bhushan, Manjul (Wilmington, DE)

    1982-01-01

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

  1. Thin film photovoltaic device

    DOEpatents

    Catalano, A.W.; Bhushan, M.

    1982-08-03

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

  2. Thin-film optical initiator

    DOEpatents

    Erickson, Kenneth L. (Albuquerque, NM)

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  3. NMR characterization of thin films

    DOEpatents

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  4. NMR characterization of thin films

    DOEpatents

    Gerald, II, Rex E. (Brookfield, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Homer Glen, IL); Diaz, Rocio (Chicago, IL); Vukovic, Lela (Westchester, IL)

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  5. Thin film photovoltaic cell

    DOEpatents

    Meakin, John D. (Newark, DE); Bragagnolo, Julio (Newark, DE)

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  6. Thin Film Reliability SEMICONDUCTORS

    E-print Network

    , and sensors. Objective Impact and Customers · Semiconductor products represent a global market of more than of thin films and interconnects in their as-manufactured states. Such tests are particularly important the effects of process variations on performance, illustrating the importance of novel metrologies during

  7. Thin film ellipsometry metrology

    NASA Astrophysics Data System (ADS)

    Durgapal, Prabha; Ehrstein, James R.; Nguyen, Nhan V.

    1998-11-01

    A wide variety of commercial ellipsometers are available in the market today. They all measure the change in the state of polarization of light on reflection, but the measurement techniques adopted vary from instrument to instrument. Further, the models used to evaluate the thickness and refractive index of the oxide film during analysis of measurement data vary in complexity. The two main techniques of measurement are single wavelength ellipsometry and spectroscopic ellipsometry. The NIST Standard Reference Materials available today are based on conventional single wavelength ellipsometry. We discuss the challenges encountered in providing reference materials by using spectroscopic ellipsometry. First, the limits of conventional single wavelength ellipsometric determination of film thickness are investigated and then possible new technologies are explored. We present a discussion comparing the different types of instruments available and how their unique designs affect the accuracy of thickness determinations. Manufacturing, and accurate determination, of thickness of films this thin (<10 nm) is a challenging task. Results from independent ellipsometric measurements on two different types of instruments are compared for the case of ultra thin thermally grown silicon dioxide films on silicon crystal substrates. Stability curves for the thickness of thin dielectric films over a period of two years are also presented.

  8. Percolation effect in thick film superconductors

    SciTech Connect

    Sali, R.; Harsanyi, G. [Technical Univ. of Budapest (Hungary)

    1994-12-31

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T{sub c} and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm{sup 2}. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  9. Biomimetic thin film deposition

    SciTech Connect

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  10. thin films as absorber

    NASA Astrophysics Data System (ADS)

    González, J. O.; Shaji, S.; Avellaneda, D.; Castillo, G. A.; Das Roy, T. K.; Krishnan, B.

    2014-09-01

    Photovoltaic structures were prepared using AgSb(S x Se1- x )2 as absorber and CdS as window layer at various conditions via a hybrid technique of chemical bath deposition and thermal evaporation followed by heat treatments. Silver antimony sulfo selenide thin films [AgSb(S x Se1- x )2] were prepared by heating multilayers of sequentially deposited Sb2S3/Ag dipped in Na2SeSO3 solution, glass/Sb2S3/Ag/Se. For this, Sb2S3 thin films were deposited from a chemical bath containing SbCl3 and Na2S2O3. Then, Ag thin films were thermally evaporated on glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of dipping was varied as 3, 4 and 5 h. Two different heat treatments, one at 350 °C for 20 min in vacuum followed by a post-heat treatment at 325 °C for 2 h in Ar, and the other at 350 °C for 1 h in Ar, were applied to the multilayers of different configurations. X-ray diffraction results showed the formation of AgSb(S x Se1- x )2 thin films as the primary phase and AgSb(S,Se)2 and Sb2S3 as secondary phases. Morphology and elemental detection were done by scanning electron microscopy and energy dispersive X-ray analysis. X-ray photoelectron spectroscopic studies showed the depthwise composition of the films. Optical properties were determined by UV-vis-IR transmittance and reflection spectral analysis. AgSb(S x Se1- x )2 formed at different conditions was incorporated in PV structures glass/FTO/CdS/AgSb(S x Se1- x )2/C/Ag. Chemically deposited post-annealed CdS thin films of various thicknesses were used as window layer. J- V characteristics of the cells were measured under dark and AM1.5 illumination. Analysis of the J- V characteristics resulted in the best solar cell parameters of V oc = 520 mV, J sc = 9.70 mA cm-2, FF = 0.50 and ? = 2.7 %.

  11. Thin film composite electrolyte

    DOEpatents

    Schucker, Robert C. (The Woodlands, TX)

    2007-08-14

    The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

  12. Thin film interconnect processes

    NASA Astrophysics Data System (ADS)

    Malik, Farid

    Interconnects and associated photolithography and etching processes play a dominant role in the feature shrinkage of electronic devices. Most interconnects are fabricated by use of thin film processing techniques. Planarization of dielectrics and novel metal deposition methods are the focus of current investigations. Spin-on glass, polyimides, etch-back, bias-sputtered quartz, and plasma-enhanced conformal films are being used to obtain planarized dielectrics over which metal films can be reliably deposited. Recent trends have been towards chemical vapor depositions of metals and refractory metal silicides. Interconnects of the future will be used in conjunction with planarized dielectric layers. Reliability of devices will depend to a large extent on the quality of the interconnects.

  13. Using Superconducting Thin Films in Microwave Lines

    NASA Technical Reports Server (NTRS)

    Genkin, Varery

    1997-01-01

    High temperature superconductors(HTS) and microwaves devices form the ideal partnership. The application of superconductors in microwave devices, components and systems allows the reduction in size, power consumption and insertion loss. The surface resistance of high-Tc superconductors has been found to be two orders of magnitude lower than normal conducting copper materials. The reduction in size and power requirements, which together both lead to a reduction in system mass, coupled with reasonably accessible operating temperatures, suggest that HTS microwave components should find ready application in satellite communications systems. At present, multi- channeling communication networks demand filters with narrow bandwidth in order to allow the available RF frequency spectrum to be partitioned into small frequency bands, -and possible variation of dielectric constant from substrate to substrate is undesirable. Microwave multiplexers demand the fabrication of two identical filters in each channel. Thus, the filter with tuning function is preferable. Tunable filters are the critical component for phased array antennas in order to electronically steer the radiated beam. To fabricate a tunable filter that uses an electric field for operation, one would like a material that provides a large change on dielectric constant for a given electric field, yet has a relatively low tangent in order to minimize the insertion loss of the device. Ferroelectrics have been the materials of choice. Their large dielectric constant sufficiently increases the coupling between microwave resonators and its dependence on electric field provides timability. Development of technology promises to diminish tangent loss. The use of thin ferroelectric films sufficiently decreases insertion losses keeping considerable potential for applications. NASA Lewis Research Center is the one of the leading centers in investigation of superconductors/ferroelectric tunable components for microwave devices. A large number of possible microwave devices were fabricated and tested on the basis of thin film multilayer superconductor-ferroelectric structures. In major cases the systems with edge-coupling scheme were investigated. Dr. Genkin has recently focused on the new potentialities which implements the using of thin ferroelectric films in filters fabricated with end-coupled microstrip lines. Numerical modeling shows that these systems have large potential for application in tunable narrow- and wide-bandpass filters in the frequency range 10-20 GHz. The phase shifter with end-coupled resonant sections was fabricated and tested. Experimental results show large tunability, particular in low voltages. The possible optimization of this structure promises to improve the obtained result and to reach the low level of insertion losses.

  14. Thin film hydrogen sensor

    DOEpatents

    Lauf, Robert J. (Oak Ridge, TN); Hoffheins, Barbara S. (Knoxville, TN); Fleming, Pamela H. (Oak Ridge, TN)

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  15. Thin film ion conducting coating

    DOEpatents

    Goldner, Ronald B. (Lexington, MA); Haas, Terry (Sudbury, MA); Wong, Kwok-Keung (Watertown, MA); Seward, George (Arlington, MA)

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  16. Thin film atomic hydrogen detectors

    NASA Technical Reports Server (NTRS)

    Gruber, C. L.

    1977-01-01

    Thin film and bead thermistor atomic surface recombination hydrogen detectors were investigated both experimentally and theoretically. Devices were constructed on a thin Mylar film substrate. Using suitable Wheatstone bridge techniques sensitivities of 80 microvolts/2x10 to the 13th power atoms/sec are attainable with response time constants on the order of 5 seconds.

  17. Ferromagnetic thin films

    DOEpatents

    Krishnan, K.M.

    1994-12-20

    A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

  18. Ferromagnetic thin films

    DOEpatents

    Krishnan, Kannan M. (Berkeley, CA)

    1994-01-01

    A ferromagnetic .delta.-Mn.sub.1-x Ga.sub.x thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of .delta.-Mn.sub.1-x Ga.sub.x overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of .delta.-Mn.sub.1-x Ga.sub.x and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4 .+-.0.05.

  19. Polyimide Aerogel Thin Films

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  20. Superconducting properties of iron chalcogenide thin films

    NASA Astrophysics Data System (ADS)

    Mele, Paolo

    2012-10-01

    Iron chalcogenides, binary FeSe, FeTe and ternary FeTexSe1-x, FeTexS1-x and FeTe:Ox, are the simplest compounds amongst the recently discovered iron-based superconductors. Thin films of iron chalcogenides present many attractive features that are covered in this review, such as: (i) easy fabrication and epitaxial growth on common single-crystal substrates; (ii) strong enhancement of superconducting transition temperature with respect to the bulk parent compounds (in FeTe0.5Se0.5, zero-resistance transition temperature Tc0bulk = 13.5 K, but Tc0film = 19 K on LaAlO3 substrate); (iii) high critical current density (Jc ˜ 0.5 ×106 A cm2 at 4.2 K and 0 T for FeTe0.5Se0.5 film deposited on CaF2, and similar values on flexible metallic substrates (Hastelloy tapes buffered by ion-beam assisted deposition) with a weak dependence on magnetic field; (iv) high upper critical field (˜50 T for FeTe0.5Se0.5, Bc2(0), with a low anisotropy, ? ˜ 2). These highlights explain why thin films of iron chalcogenides have been widely studied in recent years and are considered as promising materials for applications requiring high magnetic fields (20-50 T) and low temperatures (2-10 K).

  1. Fabrication of high-quality superconductor-insulator-superconductor junctions on thin SiN membranes

    NASA Technical Reports Server (NTRS)

    Garcia, Edouard; Jacobson, Brian R.; Hu, Qing

    1993-01-01

    We have successfully fabricated high-quality and high-current density superconductor-insulator-superconductor (SIS) junctions on freestanding thin silicon nitride (SIN) membranes. These devices can be used in a novel millimeter-wave and THz receiver system which is made using micromachining. The SIS junctions with planar antennas were fabricated first on a silicon wafer covered with a SiN membrane, the Si wafer underneath was then etched away using an anisotropic KOH etchant. The current-voltage characteristics of the SIS junctions remained unchanged after the whole process, and the junctions and the membrane survived thermal cycling.

  2. Surfactant instabilities on thin films

    E-print Network

    Aessopos, Angelica

    2005-01-01

    The deposition of a surfactant drop over a thin liquid film may be accompanied by a fingering instability. In this work, we present experimental results which identify the critical parameters that govern the shape and ...

  3. Spontaneous vortices in ferromagnet-superconductor systems

    E-print Network

    Wei, Hongduo

    2006-08-16

    We study the interaction between superconductors and ferromagnets in two systems: a ferromagnet-superconductor bilayer, and a thin superconducting film with a periodic array of magnetic dots upon it, with spontaneous vortices appearing...

  4. Thin film cell development workshop report

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.

    1991-01-01

    The Thin Film Development Workshop provided an opportunity for those interested in space applications of thin film cells to debate several topics. The unique characteristics of thin film cells as well as a number of other issues were covered during the discussions. The potential of thin film cells, key research and development issues, manufacturing issues, radiation damage, substrates, and space qualification of thin film cells were discussed.

  5. Vertically Aligned Nanocomposite Thin Films

    E-print Network

    Bi, Zhenxing

    2012-07-16

    and epitaxial growth ability on given substrates. In the present work, we investigated unique epitaxial two-phase VAN (BiFeO3)x:(Sm2 O3)1-x and (La0.7Sr0.3MnO3)x:(Mn3O4)1-x thin film systems by pulsed laser deposition. These VAN thin films exhibit a highly...

  6. Mechanical properties of thin films

    Microsoft Academic Search

    William D. Nix

    1989-01-01

    The mechanical properties of thin films on substrates are described and studied. It is shown that very large stresses may\\u000a be present in the thin films that comprise integrated circuits and magnetic disks and that these stresses can cause deformation\\u000a and fracture to occur. It is argued that the approaches that have proven useful in the study of bulk structural

  7. Thin-Film Power Transformers

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.

    1995-01-01

    Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

  8. Process for forming epitaxial perovskite thin film layers using halide precursors

    DOEpatents

    Clem, Paul G. (Albuquerque, NM); Rodriguez, Mark A. (Albuquerque, NM); Voigt, James A. (Corrales, NM); Ashley, Carol S. (Albuquerque, NM)

    2001-01-01

    A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

  9. Oxide thin film based inverse superconducting spin switches

    Microsoft Academic Search

    Norbert M. Nemes; C. Visani; C. Miller; M. Rocci; F. Bruno; J. Garcia-Barriocanal; Z. Sefrioui; C. Leon; J. Santamaria; M. Iglesias; F. Mompean; M. Garcia-Hernandez; A. Hoffmann; S. G. E. Te Velthuis

    2009-01-01

    Thin film F\\/S\\/F trilayers made of YBa2Cu3O7 (S, YBCO) and La0.7Ca0.3MnO3 (F, LCMO) behave as inverse superconducting spin switches (SSS) as the critical temperature of the superconductor depends on the relative orientation of the magnetization of the F layers in a way that the resistivity is increased in the antiparallel configuration. This is caused by enhanced pair-breaking due to the

  10. Vapor deposition of thin films

    DOEpatents

    Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  11. Epitaxial antiperovskite superconducting CuNNi3 thin films synthesized by chemical solution deposition.

    PubMed

    Hui, Zhenzhen; Tang, Xianwu; Shao, Dingfu; Lei, Hechang; Yang, Jie; Song, Wenhai; Luo, Hongmei; Zhu, Xuebin; Sun, Yuping

    2014-10-28

    Epitaxial antiperovskite superconducting CuNNi3 thin films have been grown by chemical solution deposition. The film is a type II superconductor and shows a Tc of 3.2 K with a transition of 0.13 K. The Hc2(0) and ?0 are estimated to be 8.1 kOe and 201 Å, respectively. PMID:25197779

  12. Quantum (T=0) superconductor-metal transitions in highly conducting films

    E-print Network

    Fominov, Yakov

    Quantum (T=0) superconductor-metal transitions in highly conducting films B.Spivak University-wave superconductor-metal transition in an external magnetic field b. Quantum S-wave superconductor-metal transition as a function of disorder c. Quantum D-wave superconductor-metal transition as a function of disorder d

  13. Optical and electrical properties of thin superconducting films

    NASA Technical Reports Server (NTRS)

    Covington, Billy C.; Jing, Feng Chen

    1990-01-01

    Infrared spectroscopic techniques can provide a vital probe of the superconducting energy gap which is one of the most fundamental physical properties of superconductors. Currently, the central questions regarding the optical properties of superconductors are how the energy gap can be measured by infrared techniques and at which frequency the gap exists. An effective infrared spectroscopic method to investigate the superconducting energy gap, Eg, was developed by using the Bomem DA 3.01 Fourier Transformation Spectrophotometer. The reflectivity of a superconducting thin film of YBaCuO deposited on SrTiO3 was measured. A shoulder was observed in the superconducting state reflectance R(sub S) at 480/cm. This gives a value of Eg/kT(sub c) = 7.83, where k is the Boltzmann constant and T(sub c) is the superconducting transition temperature, from which, it is suggested that YBaCuO is a very strong coupling superconductor.

  14. Drying of thin colloidal films

    NASA Astrophysics Data System (ADS)

    Routh, Alexander F.

    2013-04-01

    When thin films of colloidal fluids are dried, a range of transitions are observed and the final film profile is found to depend on the processes that occur during the drying step. This article describes the drying process, initially concentrating on the various transitions. Particles are seen to initially consolidate at the edge of a drying droplet, the so-called coffee-ring effect. Flow is seen to be from the centre of the drop towards the edge and a front of close-packed particles passes horizontally across the film. Just behind the particle front the now solid film often displays cracks and finally the film is observed to de-wet. These various transitions are explained, with particular reference to the capillary pressure which forms in the solidified region of the film. The reasons for cracking in thin films is explored as well as various methods to minimize its effect. Methods to obtain stratified coatings through a single application are considered for a one-dimensional drying problem and this is then extended to two-dimensional films. Different evaporative models are described, including the physical reason for enhanced evaporation at the edge of droplets. The various scenarios when evaporation is found to be uniform across a drying film are then explained. Finally different experimental techniques for examining the drying step are mentioned and the article ends with suggested areas that warrant further study.

  15. Levitation force from high-Tc superconducting thin-film disks Anjali B. Riise, T. H. Johansen, and H. Bratsberg

    E-print Network

    Johansen, Tom Henning

    a permanent magnet and superconducting thin film are reported. Measurements of the force Fz and magnetic-0 I. INTRODUCTION The force on a superconductor placed in the vicinity of a permanent magnet PM levitation force it is required that the superconductor is experiencing a nonuni- form magnetic field. During

  16. Thin films under chemical stress

    SciTech Connect

    Not Available

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  17. Characterization of sculptured thin films

    SciTech Connect

    Ryan, Joseph V.; Horn, Mark; Lakhtakia, Ashlesh; Pantano, C. G.

    2004-05-11

    Physical vapor deposition can be used to synthesize sculptured thin films with high surface areas. Highly directional vapor deposition onto a tilted, rotating substrate has been shown to produce nanostructured materials with controlled columnar features, including zig-zag, cusp, chevron, and helical geometries. Nanoporous coatings such as these are desirable for optical sensing applications due to their accessible high surface area, but few techniques are available to quantify the surface area of thin films. Electron beam and thermal evaporation techniques are used to synthesize highly porous thin films from silicon dioxide and a germanium antimony selenide chalcogenide glass in order to explore their potential for optical applications in both the visible and infrared spectral ranges. Characterization has been performed using nitrogen adsorption isotherms obtained with a quartz crystal microbalance. It is shown that surface area can be increased up to 375 times that of a flat film by deposition at oblique angles. A nitrogen adsorption technique is introduced as a means to examine the porosity of sculptured thin films at a nanoscale.

  18. Low work function, stable thin films

    DOEpatents

    Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

    2000-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  19. Thin film-coated polymer webs

    DOEpatents

    Wenz, Robert P. (Cottage Grove, MN); Weber, Michael F. (Shoreview, MN); Arudi, Ravindra L. (Woodbury, MN)

    1992-02-04

    The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

  20. Semiconductor-nanocrystal/conjugated polymer thin films

    DOEpatents

    Alivisatos, A. Paul (Oakland, CA); Dittmer, Janke J. (Munich, DE); Huynh, Wendy U. (Munich, DE); Milliron, Delia (Berkeley, CA)

    2010-08-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  1. Nanomechanical properties of hydrated organic thin films

    E-print Network

    Choi, Jae Hyeok

    2007-01-01

    Hydrated organic thin films are biological or synthetic molecularly thin coatings which impart a particular functionality to an underlying substrate and which have discrete water molecules associated with them. Such films ...

  2. Diamond Thin Films Handbook David S. Dandy

    E-print Network

    Dandy, David

    1 Diamond Thin Films Handbook Chapter 4 David S. Dandy Department of Chemical Engineering Colorado Sandia National Laboratories Albuquerque, New Mexico 87185 To appear in Diamond Thin Films Handbook J...............................................................................................................................3 II. Gas-phase processes in CVD diamond

  3. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  4. Thin Film Solid Lubricant Development

    NASA Technical Reports Server (NTRS)

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  5. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

    1996-12-31

    Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

  6. Finding the boson-number distributions in superconducting thin-film rings

    NASA Astrophysics Data System (ADS)

    Agafonov, A. I.

    2014-09-01

    A theory of the infrared (IR)-field-induced single-photon generation by the narrow thin-film superconducting rings made of the isotropic s-wave pairing type-II superconductors is presented. It is shown that statistical measurements of the energies of photons emitted by the same current-carrying ring prepared initially in the same quantum state, allow to find the number distribution of Cooper pairs in the superconductor.

  7. Thin films and uses

    DOEpatents

    Baskaran, Suresh (Kennewick, WA); Graff, Gordon L. (Kennewick, WA); Song, Lin (Richland, WA)

    1998-01-01

    The invention provides a method for synthesizing a titanium oxide-containing film comprising the following steps: (a) preparing an aqueous solution of a titanium chelate with a titanium molarity in the range of 0.01M to 0.6M. (b) immersing a substrate in the prepared solution, (c) decomposing the titanium chelate to deposit a film on the substrate. The titanium chelate maybe decomposed acid, base, temperature or other means. A preferred method provides for the deposit of adherent titanium oxide films from C2 to C5 hydroxy carboxylic acids. In another aspect the invention is a novel article of manufacture having a titanium coating which protects the substrate against ultraviolet damage. In another aspect the invention provides novel semipermeable gas separation membranes, and a method for producing them.

  8. Superconducting and insulating phases of disordered FeSe thin films

    NASA Astrophysics Data System (ADS)

    Schneider, Rudolf; Zaitsev, Alexander G.; Fuchs, Dirk; v. Löhneysen, Hilbert

    2015-01-01

    The temperature-dependent electronic transport on the superconducting and insulating sides of the superconductor-insulator transition in disordered quasi-two-dimensional textured FeSe thin films is reported. The transition is driven by gradually decreasing the thickness of individual films, thus increasing disorder. In the superconducting phase pronounced resistance tails evolve when the thickness decreases toward the critical thickness of the superconductor-insulator transition. The resistance tails are described reasonably well by the inverse Arrhenius law originally used to account for electronic transport in disordered granular thin films of conventional superconductors below the bulk transition temperature. The transport in the insulating phase is characterized by thermally activated variable range hopping.

  9. High permittivity thin film nanolaminates

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Solanki, R.; Roberds, B.; Bai, G.; Banerjee, I.

    2000-02-01

    Thin (˜10 nm) films comprising of Ta2O5-HfO2, Ta2O5-ZrO2, and ZrO2-HfO2 nanolaminates were deposited and characterized for possible gate dielectric applications. These films were deposited on silicon substrates using atomic layer deposition. The dielectric constants of these films were in 12-14 range and the leakage currents in 2.6×10-8-4.2×10-7 A/cm2 range at 1 MV/cm electric field. It was found that as these films were made thinner, the value of their dielectric constant dropped compared to their bulk values. The dominant leakage current mechanism at low electric fields was determined to be Schottky emission, whereas Poole-Frenkel emission dominated at higher fields.

  10. Viscoelastic Dewetting of Constrained Polymer Thin Films SYLVAIN GABRIELE,1

    E-print Network

    Raphael, Elie

    Viscoelastic Dewetting of Constrained Polymer Thin Films SYLVAIN GABRIELE,1 PASCAL DAMMAN,1 SE the stability and dewetting dynamics of viscoelastic polymer thin films. The dewetting of polystyrene close Keywords: dewetting instability; interfaces; polystyrene; thin films; viscoelasticity INTRODUCTION Thin

  11. high-k thin films

    NASA Astrophysics Data System (ADS)

    Sahiner, M. A.; Lysaght, P. S.; Price, J.; Kirsch, P. D.; Woicik, J. C.; Klump, A.; Reehil, C.; Manners, W. A.; Nabizadeh, A.

    2014-10-01

    The local symmetries around the Hf sites in thin films of Hf1- x Zr x O2/Si(100) were probed using grazing incidence extended X-ray absorption fine-structure spectroscopy (EXAFS). The effects of the Zr incorporation on the local crystal symmetries were investigated using Hf L3 EXAFS at the Beamline X23A2 of the Brookhaven National Laboratory. The Zr ratios in the various films were set to between 0.0 and 1.0. Significant changes in the local environment were observed for x = 0.25 or greater values. For x = 0.0, the film local structure around Hf sites remain in the equilibrium monoclinic phase as referenced from our previous studies on HfO2 thin films on Si(100). When Zr is introduced, tetragonal symmetry around the Hf atom appears and becomes dominant at x = 0.63. Using the EXAFS theoretical simulations and non-linear least-square fit results, the fractions of the monoclinic versus tetragonal phases were identified in each film.

  12. Thin film buried anode battery

    DOEpatents

    Lee, Se-Hee (Lakewood, CO); Tracy, C. Edwin (Golden, CO); Liu, Ping (Denver, CO)

    2009-12-15

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  13. Sputter deposition for multi-component thin films

    DOEpatents

    Krauss, A.R.; Auciello, O.

    1990-05-08

    Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams. 10 figs.

  14. Exchange coupled thin film magnets

    NASA Astrophysics Data System (ADS)

    Andreescu, Radu

    The object of this work is the study of structural and magnetic properties of Sm-Co based thin films. One important aim is to obtain large energy-product values, the primary requirement in the permanent magnet industry. The materials are prepared by sputter deposition and an anneal at elevated temperature is required to crystallize the film and form the hard magnetic phases. Nb is used as a buffer layer between the Si substrate and the Sm-Co film due to its mechanical hardness and lack of chemical reactivity. The <> composition SmCo5 is prepared first in nanocrystalline form. High coercivities (up to 37 kOe) are obtained along with rather modest values for energy product (˜5 MG.Oe). Multilayers of the form SmCo5/Co are prepared next. An anneal leads to the destruction of the multilayers and the crystallization of SmCo 5 and Co phases. The composition of these films is chosen to exploit the exchange-spring mechanism between the hard (SmCo5) and soft (Co) magnetic phases, in an attempt to obtain higher energy products. These films have crystallite size of the order 10 nm---a requirement if the soft and hard magnetic phases are to be strongly coupled. A large increase in energy product is observed (the best value ˜12 MG.Oe) compared to the SmCo5 films. Nominally homogeneous Sm-Co films were then prepared and after an anneal crystallites of size about 15 nm are formed. The energy product here is larger than in our earlier films due primarily to a larger magnetic moment and a strong coupling between soft and hard phases. A value of 19 MG.Oe is reported, which is the highest value reported so far for a Sm-Co-based thin film permanent magnet. Finally, Sm-Co films with Fe, Cu, and Zr additions are prepared. Their energy product is in between the SmCo5 magnets and SmCo5/Co magnets. The coercivity is 39 kOe, the best coercivity obtained in this project. We use the micromagnetic theories Gaunt and Kronmuller to study the mechanism of coercivity in the films and find that pinning of domain walls is the primary coercivity mechanism.

  15. The road to magnesium diboride thin films, Josephson junctions and SQUIDs

    Microsoft Academic Search

    Alexander Brinkman; Dragana Mijatovic; Hans Hilgenkamp; Guus Rijnders; Ingrid Oomen; Dick Veldhuis; Frank Roesthuis; Horst Rogalla; Dave H. A. Blank

    2003-01-01

    The remarkably high critical temperature at which magnesium diboride (MgB2) undergoes transition to the superconducting state, Tc approx 40 K, has aroused great interest and has encouraged many groups to explore the properties and application potential of this novel superconductor. For many electronic applications and further basic studies, the availability of superconducting thin films is of great importance. Several groups

  16. SUPERCONDUCTING PROPERTIES OF ALUMINIUM THIN FILMS AFTER ION IMPLANTATION AT LIQUID HELIUM TEMPERATURES (*)

    E-print Network

    Boyer, Edmond

    L-271 SUPERCONDUCTING PROPERTIES OF ALUMINIUM THIN FILMS AFTER ION IMPLANTATION AT LIQUID HELIUM concentration near AlH2. It is well-known [1] that the superconducting transition temperature Tc of metals as in the electronic density of states N(O) at the Fermi surface. In the case of weak-coupling superconductors

  17. Zinc oxide thin film acoustic sensor

    NASA Astrophysics Data System (ADS)

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Mansour, Hazim Louis; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah

    2013-12-01

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  18. Zinc oxide thin film acoustic sensor

    SciTech Connect

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah [Department of Physics , College of Science, Al-Mustansiriyah University, Baghdad (Iraq); Mansour, Hazim Louis [Department of Physics , College of Education, Al-Mustansiriyah University, Baghdad (Iraq)

    2013-12-16

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  19. Preparation of thin ceramic films via an aqueous solution route

    DOEpatents

    Pederson, Larry R. (Kennewick, WA); Chick, Lawrence A. (Richland, WA); Exarhos, Gregory J. (Richland, WA)

    1989-01-01

    A new chemical method of forming thin ceramic films has been developed. An aqueous solution of metal nitrates or other soluble metal salts and a low molecular weight amino acid is coated onto a substrate and pyrolyzed. The amino acid serves to prevent precipitation of individual solution components, forming a very viscous, glass-like material as excess water is evaporated. Using metal nitrates and glycine, the method has been demonstrated for zirconia with various levels of yttria stabilization, for lanthanum-strontium chromites, and for yttrium-barium-copper oxide superconductors on various substrates.

  20. Printing organic thin-film transistor technology

    Microsoft Academic Search

    Cheng-Chung Lee; Jia-Chong Ho; Tamg-Shiang Hu; Yu-Wu Wang

    2005-01-01

    Si thin-film transistor (a-Si TFT and LTPS-TFT) and organic thin film transistor (OTFT) based on conjugated organic semiconductor have become attractive for use in flat panel display, smart cards, RFID tags and large area sensors. An organic thin-film transistor (OTFT) can be formed on plastic substrate due to its low process temperature, <150°C. Therefore, the manufacturing cost of OTFT is

  1. Method of producing amorphous thin films

    DOEpatents

    Brusasco, R.M.

    1992-09-01

    Disclosed is a method of producing thin films by sintering which comprises: (a) coating a substrate with a thin film of an inorganic glass forming material possessing the capability of being sintered; and (b) irradiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof. Also disclosed is the article produced by the method claimed. 4 figs.

  2. Method of producing amorphous thin films

    DOEpatents

    Brusasco, Raymond M. (Livermore, CA)

    1992-01-01

    Disclosed is a method of producing thin films by sintering which comprises: a. coating a substrate with a thin film of an inorganic glass forming parulate material possessing the capability of being sintered, and b. irridiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof. Also disclosed is the article produced by the method claimed.

  3. Doping in zinc oxide thin films

    Microsoft Academic Search

    Zheng Yang

    2009-01-01

    Doping in zinc oxide (ZnO) thin films is discussed in this dissertation. The optimizations of undoped ZnO thin film growth using molecular-beam epitaxy (MBE) are discussed. The effect of the oxygen ECR plasma power on the growth rate, structural, electrical, and optical properties of the ZnO thin films were studied. It was found that larger ECR power leads to higher

  4. Barium ferrite thin-film recording media

    Microsoft Academic Search

    Xiaoyu Sui; Matthias Scherge; Mark H. Kryder; John E. Snyder; Vincent G. Harris; Norman C. Koon

    1996-01-01

    Both longitudinal and perpendicular barium ferrite thin films are being pursued as overcoatless magnetic recording media. In this paper, prior research on thin-film Ba ferrite is reviewed and the most recent results are presented. Self-textured high-coercivity longitudinal Ba ferrite thin films have been achieved using conventional rf diode sputtering. Microstructural studies show that c-axis in-plane oriented grains have a characteristic

  5. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    Marshall Space Flight Center (MSFC) is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) to deposit hard thin film on stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  6. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  7. Dynamic delamination of patterned thin films

    Microsoft Academic Search

    Soma S. V. Kandula; Phuong Tran; Philippe H. Geubelle; Nancy R. Sottos

    2008-01-01

    We investigate laser-induced dynamic delamination of a patterned thin film on a substrate. Controlled delamination results from our insertion of a weak adhesion region beneath the film. The inertial forces acting on the weakly bonded portion of the film lead to stable propagation of a crack along the film\\/substrate interface. Through a simple energy balance, we extract the critical energy

  8. Thin film solar energy collector

    DOEpatents

    Aykan, Kamran (Monmouth Beach, NJ); Farrauto, Robert J. (Westfield, NJ); Jefferson, Clinton F. (Millburn, NJ); Lanam, Richard D. (Westfield, NJ)

    1983-11-22

    A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

  9. Morphological stability of thin films

    SciTech Connect

    Gray, L.J.; Chisholm, M.F.; Kaplan, T.

    1993-12-31

    The boundary element method for elastostatics is applied to a thin stability problem arising in solid state surface science. An aim of this work is to determine the morphology of Ge deposited on a Si substrate. Nonstandard boundary conditions at the material interface are used to model the epitaxially grown film. In addition to determining the deformed geometry, it is also necessary to compute the surface stress tensor. Although the surface displacement at the junction between the interface and the Si free surface is not differentiable, the hypersingular integral equation for surface stress can still be used. These techniques are described along with results from 2-D calculations.

  10. Transparent conducting oxide films for thin film silicon photovoltaics

    Microsoft Academic Search

    W. Beyer; J. Hupkes; H. Stiebig

    2007-01-01

    The requirements for applications of transparent conducting oxide (TCO) films in thin film silicon solar cells are reviewed with a focus on sputtered Al doped zinc oxide and fluorine doped tin oxide films. TCO films are employed as a front contact and as part of a highly reflective back contact so that the silicon absorber layer is embedded by TCO

  11. thin films by thermal annealing

    NASA Astrophysics Data System (ADS)

    Liu, Xiang; Yin, Xue-Peng; Chen, Qing-Ming; Zhang, Hui; Zhang, Shao-Chun

    2014-09-01

    La2/3Ba1/3MnO3:Ag0.04 (LBMO:Ag0.04) thin films were prepared on single crystalline (001)-orientated LaAlO3 substrates by pulsed laser deposition technique. Thermal annealing with temperatures of 780, 800 and 820 °C has been investigated to improve electrical properties of the films. All the samples are shown along the (00 l) orientation in rhombohedral structure with space group. With thermal annealing temperature increasing, insulator-metal transition temperature ( T p) and resistivity at T p () of the epilayer reach optimal value of 288 K and 0.03 ?·cm, respectively. The electrical properties improvement of the LBMO:Ag0.04 films is due to an improved film crystallization, oxygen balance and photon scattering suppression. The fitting curves show that the region of ferro-magnetic metallic (FM, T < T p) is fitted with grain/domain boundary, electron-electron and magnon scattering mechanism, as well as the region of para-magnetic insulating (PI, T > T p) is fitted with adiabatic small polaron hopping mechanism.

  12. Fabrication of Microporous Thin Films from Polyelectrolyte Multilayers

    E-print Network

    Barrett, Christopher

    Fabrication of Microporous Thin Films from Polyelectrolyte Multilayers J. D. Mendelsohn, C. J, highly uniform microporous thin films. Multilayers of weak polyelectrolytes were assembled onto silicon and biomaterial applications. Introduction The fabrication of polyelectrolyte multilayer thin films has received

  13. Electro-deposition of superconductor oxide films

    DOEpatents

    Bhattacharya, Raghu N. (Littleton, CO)

    2001-01-01

    Methods for preparing high quality superconducting oxide precursors which are well suited for further oxidation and annealing to form superconducting oxide films. The method comprises forming a multilayered superconducting precursor on a substrate by providing an electrodeposition bath comprising an electrolyte medium and a substrate electrode, and providing to the bath a plurality of precursor metal salts which are capable of exhibiting superconducting properties upon subsequent treatment. The superconducting precursor is then formed by electrodepositing a first electrodeposited (ED) layer onto the substrate electrode, followed by depositing a layer of silver onto the first electrodeposited (ED) layer, and then electrodepositing a second electrodeposited (ED) layer onto the Ag layer. The multilayered superconducting precursor is suitable for oxidation at a sufficient annealing temperature in air or an oxygen-containing atmosphere to form a crystalline superconducting oxide film.

  14. Electrostatic thin film chemical and biological sensor

    DOEpatents

    Prelas, Mark A. (Columbia, MO); Ghosh, Tushar K. (Columbia, MO); Tompson, Jr., Robert V. (Columbia, MO); Viswanath, Dabir (Columbia, MO); Loyalka, Sudarshan K. (Columbia, MO)

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  15. Thin film characterization using resonant ultrasound spectroscopy

    Microsoft Academic Search

    J. R. Gladden; Jin H. So; Rajdeep Pradhan; J. D. Maynard

    2002-01-01

    With mechanical and electrical components approaching nanoscale dimensions, there is great interest in the properties of thin films. Some properties, such as structure and phase transitions, can be probed with measurements of elastic constants. We have been using Resonant Ultrasound Spectroscopy (RUS) to probe such properties for a variety of thin film materials including colossal magnetoresistance (CMR) materials, carbon nanotubes,

  16. Multiferroics: progress and prospects in thin films

    Microsoft Academic Search

    R. Ramesh; Nicola A. Spaldin

    2007-01-01

    Multiferroic materials, which show simultaneous ferroelectric and magnetic ordering, exhibit unusual physical properties - and in turn promise new device applications - as a result of the coupling between their dual order parameters. We review recent progress in the growth, characterization and understanding of thin-film multiferroics. The availability of high-quality thin-film multiferroics makes it easier to tailor their properties through

  17. Thin film shape memory alloy microactuators

    Microsoft Academic Search

    P. Krulevitch; A. P. Lee; P. B. Ramsey; J. C. Trevino; M. A. Northrup

    1996-01-01

    Thin film shape memory alloys (SMAs) have the potential to become a primary actuating mechanism for mechanical devices with dimensions in the micron-to-millimeter range requiring large forces over long displacements. The work output per volume of thin film SMA microactuators exceeds that of other microactuation mechanisms such as electrostatic, magnetic, thermal bimorph, piezoelectric, and thermopneumatic, and it is possible to

  18. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, Reid A. (Bellevue, WA); Chen, Wen S. (Seattle, WA)

    1985-01-01

    A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

  19. Investigations on barium ferrite magnetic thin films

    Microsoft Academic Search

    Wenjie Pang; Hong Sun

    2002-01-01

    Summary form only given. Barium ferrite thin films are promising candidates for both longitudinal and perpendicular recording media. It is important to understand the time dependent phenomena in these thin films as many of the critical properties of magnetic recording media are directly related to it. The time dependent phenomenon is also known as magnetic viscosity. The magnetic viscosity parameter,

  20. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

    1993-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  1. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

    1995-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  2. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. [Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center; Wei, G. [Mobil Solar Energy Corp., Billerica, MA (United States); Yu, P.C. [PPG Industries, Inc., Monroeville, PA (United States)

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  3. Magnetostrictive thin films for microwave spintronics

    PubMed Central

    Parkes, D. E.; Shelford, L. R.; Wadley, P.; Holý, V.; Wang, M.; Hindmarch, A. T.; van der Laan, G.; Campion, R. P.; Edmonds, K. W.; Cavill, S. A.; Rushforth, A. W.

    2013-01-01

    Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies. Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths. Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films. We report the development of epitaxial thin films of Galfenol (Fe81Ga19) with magnetostriction as large as the best reported values for bulk material. This allows the magnetic anisotropy and microwave resonant frequency to be tuned by voltage-induced strain, with a larger magnetoelectric response and a narrower linewidth than any previously reported Galfenol thin films. The combination of these properties make epitaxial thin films excellent candidates for developing tunable devices for magnetic information storage, processing and microwave communications. PMID:23860685

  4. Characterization of Thin Films and Coatings

    Microsoft Academic Search

    Donald R. Baer; Suntharampillai Thevuthasan

    2010-01-01

    Just as the numbers and types of thin films have grown dramatically, the needs and approaches for their characterization have also expanded significantly. Adequate characterization of a film or coating depends on the process to create the coating as well as the planned or potential application(s) and expected lifetime. Characterization of a coating or film necessarily requires application of methods

  5. Thin spray film thickness measuring technique

    NASA Technical Reports Server (NTRS)

    Jones, G.; Kurtz, G. W.

    1971-01-01

    Thin spray film application depths, in the 0.0002 cm to 0.002 cm range, are measured by portable, commercially available, light density measuring device used in conjunction with glass plate or photographic film. Method is automated by using mechanical/electrical control for shutting off film applicator at desired densitometer reading.

  6. Pressure effects on strained FeSe0.5Te0.5 thin films

    NASA Astrophysics Data System (ADS)

    Gooch, M.; Lorenz, B.; Huang, S. X.; Chien, C. L.; Chu, C. W.

    2012-06-01

    The pressure effect on the resistivity and superconducting Tc of prestrained thin films of the iron chalcogenide superconductor FeSe0.5Te0.5 is studied. Films with different anion heights above the Fe layer showing different values of ambient pressure Tc's are compressed up to a pressure of 1.7 GPa. All films exhibit a significant increase of Tc with pressure. The results cannot solely be explained by a pressure-induced decrease of the anion height but other parameters have to be considered to explain the data for all films.

  7. Thin film limits for Ginzburg--Landau with strong applied magnetic fields

    E-print Network

    Stan Alama; Lia Bronsard; Bernardo Galvão-Sousa

    2009-11-06

    In this work, we study thin-film limits of the full three-dimensional Ginzburg-Landau model for a superconductor in an applied magnetic field oriented obliquely to the film surface. We obtain Gamma-convergence results in several regimes, determined by the asymptotic ratio between the magnitude of the parallel applied magnetic field and the thickness of the film. Depending on the regime, we show that there may be a decrease in the density of Cooper pairs. We also show that in the case of variable thickness of the film, its geometry will affect the effective applied magnetic field, thus influencing the position of vortices.

  8. Nanotribology of confined thin films

    NASA Astrophysics Data System (ADS)

    Drummond, Carlos Alberto

    In this dissertation I present the results of the study of the friction behavior of molecularly smooth mica surfaces confining thin films of different materials. The main objective was to improve the basic understanding of the mechanism underlying frictional processes, to assist the development of new techniques of control and reduction of frictional waste and wear. The behavior of thin films of branched hydrocarbon lubricants under shear is described in detail. The evolution of the systems to steady-state sliding from rest or after a change in sliding velocity was thoroughly studied, and the presence of different length and time scales was observed. Using a new 'extended bimorph slider' which allows continuous shearing for distances well beyond the contact diameter (asperity size) I show that the evolution to steady-state sliding in these films is governed by the distance the surfaces are sheared rather than the time. From these results it is clear that both time and distance of sliding have to be considered in order to fully describe the dynamic response of lubricants and complex fluids under shear. The behavior of linear and branched hydrocarbon films under shear is compared, and the physical reasons for the different types of transitions and friction traces observed in the two systems are discussed. Two approaches to friction reduction were investigated. First, a new method for friction control and reduction is proposed. Using a Surface Forces Apparatus modified for measuring friction forces while simultaneously inducing normal (out-of-plane) vibrations between two sliding surfaces, load- and frequency-dependent transitions between a number of "dynamic friction" states are observed. In particular, regimes of vanishingly small friction at small interfacial oscillation amplitudes are found. Despite its complexity, the phenomenon is shown to have a molecular origin. Second, a novel lubricant material was studied in detail. The tribological behavior of colloidal particles of tungsten disulfide of different structures was studied using different techniques. Shear induced material transfer (via third body processes) from the colloidal particles to the surfaces was shown to be a dominant factor in the tribological behavior observed. Both platelet and nested spherical structures were investigated. An ultrathin, ordered layer with promising lubricative properties was observed when nested particles were sheared, while WS2 platelets produced a rough and disordered transfer layer, with substantially inferior lubricating properties.

  9. Superconducting and Insulating Phases of Disordered FeSe Thin Films in a Magnetic Field

    NASA Astrophysics Data System (ADS)

    Schneider, R.; Zaitsev, A. G.; Fuchs, D.; von Löhneysen, H.

    2015-01-01

    The temperature-dependent electronic transport on the superconducting and insulating sides of the superconductor-insulator transition in disordered quasi-two-dimensional textured FeSe thin films is reported. The transition is driven by a perpendicular magnetic field applied to a film with its thickness close to the critical thickness of the thickness-, i.e., disorder-induced transition. The resistance in the superconducting phase might be dominated by thermally assisted flux flow, and in the phase diagram a metallic phase might intervene between the superconducting and insulating state at very low temperatures. In the insulating phase, weak insulating behavior is observed that can be described by weak localization theory of bosons, thus supporting the bosonic description of the superconductor-insulator transition in FeSe thin films.

  10. Antimony sulfide thin films in chemically deposited thin film photovoltaic cells

    Microsoft Academic Search

    Sarah Messina; M. T. S. Nair; P. K. Nair

    2007-01-01

    Antimony sulfide thin films of thickness ?500 nm have been deposited on glass slides from chemical baths constituted with SbCl3 and sodium thiosulfate. Smooth specularly reflective thin films are obtained at deposition temperatures from ?3 to 10 °C. The differences in the film thickness and improvement in the crystallinity and photoconductivity upon annealing the film in nitrogen are presented. These films can

  11. Crystallization of thin and ultra-thin polymer films

    NASA Astrophysics Data System (ADS)

    Wang, Yantian

    Thin and ultra-thin polymer films have received great interest due to their technological applications in the modern micro-electronic devices. It has been demonstrated that the presence of the interface and the confined geometry greatly affect configuration of the chains, segmental mobility and thermal transitions in the polymer thin films. In the semi-crystalline polymer thin films, the degree of crystallinity, crystallization dynamics, crystal morphology and lamellar orientation are different from their bulk counterparts. In this dissertation, a comprehensive study in the crystallization and melting of spun-coated thin and ultra-thin films of polyethylene-vinyl acetate)(EVA), linear low and medium density polyethylene (LLDPE and LMDPE) on selected substrates was made. The morphology, the lamellar orientation and the melting point of the films were found to have strong dependence on the film thickness and the substrate. On the strongly attractive substrate such as silicon, the film crystallized as spherulite with densely organized edge-on lamellae for the films thicker than 100nm, the lamellae packed more loosely as the film thickness decreased, until finally exhibited a dense branching morphology with mainly flat-on lamellae when the film is thinner than 15nm. A large degree of crystallinity was observed in the film as thin as 15nm. On the less absorbent substrate such as polyimide, the films crystallized in a randomly organized lamellae structure, which showed little dependence on the film thickness. On all the substrates, the melting point of the film decreased with the film thickness decrease when the film was thinner than a critical thickness, the value of which varied for different substrates. The biggest Tm depression observed was between 12°C and 38°C, depending on the substrates. The finite size effect and the reduced melting entropy caused by the confined movement of the polymer chains due to the substrate absorption were suggested to be the main reasons for the sharp Tm depression. The chain orientation inside the crystals was measured by near edge X-ray absorption fine structure (NEXAFS) spectroscopy, which showed that on the silicon substrate, the chains oriented parallel to the substrate with b axis in the radiation direction of the fibrils of the spherulite, a axis perpendicular to the film surface.

  12. BDS thin film damage competition

    SciTech Connect

    Stolz, C J; Thomas, M D; Griffin, A J

    2008-10-24

    A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

  13. Wrinkle motifs in thin films

    PubMed Central

    Budrikis, Zoe; Sellerio, Alessandro L.; Bertalan, Zsolt; Zapperi, Stefano

    2015-01-01

    On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as ‘telephone cord’ buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales. PMID:25758174

  14. Wrinkle motifs in thin films

    NASA Astrophysics Data System (ADS)

    Budrikis, Zoe; Sellerio, Alessandro L.; Bertalan, Zsolt; Zapperi, Stefano

    2015-03-01

    On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as `telephone cord' buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales.

  15. Wrinkle motifs in thin films.

    PubMed

    Budrikis, Zoe; Sellerio, Alessandro L; Bertalan, Zsolt; Zapperi, Stefano

    2015-01-01

    On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as 'telephone cord' buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales. PMID:25758174

  16. Weakly superconducting, thin-film structures as radiation detectors.

    NASA Technical Reports Server (NTRS)

    Kirschman, R. K.

    1972-01-01

    Measurements were taken with weakly superconducting quantum structures of the Notarys-Mercereau type, representing a thin superconductor film with a short region that is weakened in the sense that its transition temperature is lower than in the remaining portion of the film. The structure acts as a superconducting relaxation oscillator in which the supercurrent increases with time until the critical current of the weakened section is attained, at which moment the supercurrent decays and the cycle repeats. Under applied radiation, a series of constant-voltage steps appears in the current-voltage curve, and the size of the steps varies periodically with the amplitude of applied radiation. Measurements of the response characteristics were made in the frequency range of 10 to 450 MHz.

  17. Primary research efforts on exploring the commercial possibilities of thin film growth and materials purification in space

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The progress made on research programs in the 1987 to 1988 year is reported. The research is aimed at producing thin film semiconductors and superconductor materials in space. Sophisticated vacuum chambers and equipment were attained for the epitaxial thin film growth of semiconductors, metals and superconductors. In order to grow the best possible epitaxial films at the lowest possible temperatures on earth, materials are being isoelectronically doped during growth. It was found that isoelectrically doped film shows the highest mobility in comparison with films grown at optimal temperatures. Success was also attained in growing epitaxial films of InSb on sapphire which show promise for infrared sensitive devices in the III-V semiconductor system.

  18. VUV thin films, chapter 7

    NASA Technical Reports Server (NTRS)

    Zukic, Muamer; Torr, Douglas G.

    1993-01-01

    The application of thin film technology to the vacuum ultraviolet (VUV) wavelength region from 120 nm to 230 nm has not been fully exploited in the past because of absorption effects which complicate the accurate determination of the optical functions of dielectric materials. The problem therefore reduces to that of determining the real and imaginary parts of a complex optical function, namely the frequency dependent refractive index n and extinction coefficient k. We discuss techniques for the inverse retrieval of n and k for dielectric materials at VUV wavelengths from measurements of their reflectance and transmittance. Suitable substrate and film materials are identified for application in the VUV. Such applications include coatings for the fabrication of narrow and broadband filters and beamsplitters. The availability of such devices open the VUV regime to high resolution photometry, interferometry and polarimetry both for space based and laboratory applications. This chapter deals with the optics of absorbing multilayers, the determination of the optical functions for several useful materials, and the design of VUV multilayer stacks as applied to the design of narrow and broadband reflection and transmission filters and beamsplitters. Experimental techniques are discussed briefly, and several examples of the optical functions derived for selected materials are presented.

  19. Structural characterization of zinc stannate thin films

    Microsoft Academic Search

    D. L. Young; D. L. Williamson; T. J. Coutts

    2002-01-01

    Polycrystalline thin films of Zn2SnO4 were deposited by rf magnetron sputtering onto glass substrates. Films were characterized by ?–2? x-ray diffraction and by 119Sn conversion electron Mo¨ssbauer spectroscopy. The films were randomly oriented in a cubic spinel structure. Comparison of x-ray diffraction peak intensities with structure-factor-calculated peak intensities confirmed that the films were in an inverse spinel configuration. Mo¨ssbauer studies

  20. Structural characterization of zinc stannate thin films

    Microsoft Academic Search

    D. L. Young; D. L. Williamson; T. J. Coutts

    2002-01-01

    Polycrystalline thin films of Zn2SnO4 were deposited by rf magnetron sputtering onto glass substrates. Films were characterized by theta-2theta x-ray diffraction and by 119Sn conversion electron Mössbauer spectroscopy. The films were randomly oriented in a cubic spinel structure. Comparison of x-ray diffraction peak intensities with structure-factor-calculated peak intensities confirmed that the films were in an inverse spinel configuration. Mössbauer studies

  1. Flexible thin metal film thermal sensing system

    NASA Technical Reports Server (NTRS)

    Thomsen, Donald L. (Inventor)

    2010-01-01

    A flexible thin metal film thermal sensing system is provided. A self-metallized polymeric film has a polymeric film region and a metal surface disposed thereon. A layer of electrically-conductive metal is deposited directly onto the self-metallized polymeric film's metal surface. Coupled to at least one of the metal surface and the layer of electrically-conductive metal is a device/system for measuring an electrical characteristic associated therewith as an indication of temperature.

  2. Interfacial Effects on Pentablock Ionomer Thin Films

    NASA Astrophysics Data System (ADS)

    Etampawala, Thusitha; Ratnaweera, Dilru; Osti, Naresh; Shrestha, Umesh; Perahia, Dvora; Majewski, Jaroslaw

    2011-03-01

    The interfacial behavior of multi block copolymer thin films results from a delicate balance between inherent phase segregation due to incompatibility of the blocks and the interactions of the individual blocks with the interfaces. Here in we report a study of thin films of ABCBA penta block copolymers, anionically synthesized, comprising of centered randomly sulfonated polystyrene block to which rubbery poly-ethylenebutalene is connected, terminated by blocks of poly-t-butylstyrene, kindly provided by Kraton. AFM and neutron reflectometry studies have shown that the surface structure of pristine films depends on film thickness and ranges from trapped micelles to thin layered films. Annealing above Tg for the styrene block results in rearrangements into relatively featureless air interface. Neutron reflectivity studies have shown that annealed films forms layers whose plane are parallel to the solid substrate with the bulky block at the air interface and the ionic block at the solid interface.

  3. Aging phenomena in polystyrene thin films

    E-print Network

    Koji Fukao; Hiroki Koizumi

    2008-01-05

    The aging behavior is investigated for thin films of atactic polystyrene through measurements of complex electric capacitance. During isothermal aging process the real part of the electric capacitance increases with aging time, while the imaginary part decreases with aging time. This result suggests that the aging time dependence of the real and imaginary parts are mainly associated with change in thickness and dielectric permittivity, respectively. In thin films, the thickness depends on thermal history of aging even above the glass transition. Memory and `rejuvenation' effects are also observed in the thin films.

  4. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C.R.; Kozlowski, M.R.; Campbell, J.H.; Staggs, M.; Rainer, F.

    1995-12-05

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold. 9 figs.

  5. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C. Robert (Palo Alto, CA); Kozlowski, Mark R. (Pleasanton, CA); Campbell, John H. (Livermore, CA); Staggs, Michael (Tracy, CA); Rainer, Frank (Livermore, CA)

    1995-01-01

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

  6. An Ultra-Thin Molecular Superconductor Made from Charge Transfer Complexes

    NASA Astrophysics Data System (ADS)

    Clark, Kendal; Hassenien, A.; Khan, S.; Braun, K.-F.; Tanaka, H.; Hla, S.-W.

    2010-03-01

    A class of charge transfer molecular systems having a D2A arrangement (D = donor, A = accepter) exhibit superconductivity in the bulk and are often termed ``unusual superconductors'' based on the different nature of their superconducting states as compared to convention BCS superconductors. In this study we have formed an ultra-thin (BETS)2-GaCl4 molecular superconductor consisting of a single sheet of layered molecules composed of individual GaCl4 sandwiched between the chains of a double domino stacked BETS on a Ag(111) surface. Amazingly, the superconducting gap can still be detected in such an ultra-thin molecular layer, and the shape of the gap reveals a d-wave pairing symmetry. Moreover, real space STM spectroscopic images provide direct evidence of the superconducting site as the BETS chains. In stark contrast to the high Tc superconductors, the spectroscopic maps clearly display nanoscale electronic order indicating robust superconducting properties at this extreme spatial limit..

  7. Visible spectrometer utilizing organic thin film absorption

    E-print Network

    Tiefenbruck, Laura C. (Laura Christine)

    2004-01-01

    In this thesis, I modeled and developed a spectrometer for the visible wavelength spectrum, based on absorption characteristics of organic thin films. The device uses fundamental principles of linear algebra to reconstruct ...

  8. Magnetic properties of cobalt nitride thin films

    Microsoft Academic Search

    Morito Matsuoka; Ken'ichi Ono; Takashi Inukai

    1986-01-01

    Cobalt nitride (CoNx) thin films with a large perpendicular magnetic anisotropy are synthesized by reactive sputtering. The perpendicular magnetic anisotropy is induced by substrate heating during deposition, annealing after deposition, or ion bombardment during deposition.

  9. Solid State Thin Film Lithium Microbatteries

    E-print Network

    Shi, Z.

    Solid state thin film lithium microbatteries fabricated by pulsed-laser deposition (PLD) are suggested. During deposition the following process parameters must be considered, which are laser energy and fluence, laser pulse ...

  10. Thin film production method and apparatus

    DOEpatents

    Loutfy, Raouf O. (Tucson, AZ); Moravsky, Alexander P. (Tucson, AZ); Hassen, Charles N. (Tucson, AZ)

    2010-08-10

    A method for forming a thin film material which comprises depositing solid particles from a flowing suspension or aerosol onto a filter and next adhering the solid particles to a second substrate using an adhesive.

  11. Highly transparent solution processed In-Ga-Zn oxide thin films and thin film transistors

    Microsoft Academic Search

    Y. Wang; S. W. Liu; X. W. Sun; J. L. Zhao; G. K. L. Goh; Q. V. Vu; H. Y. Yu

    2010-01-01

    Highly transparent In-Ga-Zn oxide (IGZO) thin films were fabricated by spin coating using acetate- and chlorate-based precursors,\\u000a and thin film transistors (TFTs) were further fabricated employing these IGZO films as the active channel layer. The impact\\u000a of the post-annealing temperature on the physical properties of IGZO films and performance of IGZO TFTs were investigated.\\u000a Compared to the nitrate-based IGZO precursor,

  12. Thin-film reliability and engineering overview

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1984-01-01

    The reliability and engineering technology base required for thin film solar energy conversions modules is discussed. The emphasis is on the integration of amorphous silicon cells into power modules. The effort is being coordinated with SERI's thin film cell research activities as part of DOE's Amorphous Silicon Program. Program concentration is on temperature humidity reliability research, glass breaking strength research, point defect system analysis, hot spot heating assessment, and electrical measurements technology.

  13. Thin-film cryogenic current comparator

    Microsoft Academic Search

    H. Seppa; A. Satrapinski; M. Kiviranta; V. Virkki

    1999-01-01

    We analyze a thin-film cryogenic current comparator (CCC) intended to be used in ac measurements. Our analysis shows that by calibrating the dc ratio error of the thin-film CCC against a conventional CCC, it can be used up to 10 kHz as a sensitive and highly accurate current comparator. We have fabricated a practical 1:1 planar CCC integrated with a

  14. Biomimetic Pathways for Assembling Inorganic Thin Films

    Microsoft Academic Search

    I. A. Aksay; M. Trau; S. Manne; I. Honma; N. Yao; L. Zhou; P. Fenter; P. M. Eisenberger; S. M. Gruner

    1996-01-01

    Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100^circC and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic

  15. Nanoscale Multilayer CIS Thin Film Characterization

    Microsoft Academic Search

    R. P. Raffaelle; J. G. Mantovani; H. Forsell; D. Palacios; P. Kalmanson; O. Melendez; J. Hurley

    1997-01-01

    We have been investigating the electrochemical deposition of CdS and CuInSe2 (CIS) for use in thin film solar cells. CIS is a leading candidate for use in polycrystalline thin film photovoltaic solar cells due to its favorable optical absorption and electrical characteristics. We have incorporated this material into nanometer scale layers in which the Cu to In ratio is periodically

  16. Growth and Properties of SmFeAsO1-xFx thin films using pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Lee, Sanghan; Folkman, Chad; Hyub Baek, Seung; Felker, David; Rzchowski, Mark; Eom, Chang Beom; Jiang, Jianyi; Hellstrom, Eric

    2009-03-01

    The discovery of iron pnictide superconductors has been gaining interest due to their highest transition temperatures (Tc) among transition metal compound except cuprate systems. In iron pnictide system, Tc has been significantly enhanced by replacing elements. The growth of epitaxial thin film of this interesting compound is desirable for fundamental understanding of superconductivity and potential device applications. So far, there is no report with successful growth of epitaxial thin films with the same Tc of the bulk materials. Although several reports show Tc of thin film, the resistivity dose not reach zero down to at 4K. We have employed pulsed laser deposition for the growth of iron pnictides, SmFeAsO1-xFx, thin films on various single crystal substrates followed by ex--situ post annealing. In this talk, we will discuss the structural and superconducting properties of SmFeAsO1-xFx thin film including Tc, Jc and Hc2.

  17. Printable CIGS thin film solar cells

    NASA Astrophysics Data System (ADS)

    Fan, Xiaojuan

    2013-03-01

    Among the various thin film solar cells in the market, CuInGaSe thin film solar cells have been considered as the most promising alternatives to crystalline silicon solar cells because of their high photo-electricity conversion efficiency, reliability, and stability. However, many fabrication methods of CIGS thin film are based on vacuum processes such as evaporation and sputtering techniques which are not cost efficient. This work develops a solution method using paste or ink liquid spin-coated on glass that would be competitive to conventional ways in terms of cost effective, non-vacuum needed, and quick processing. A mixture precursor was prepared by dissolving appropriate amounts of composition chemicals. After the mixture solution was cooled, a viscous paste was prepared and ready for spin-coating process. A slight bluish CIG thin film on substrate was then put in a tube furnace with evaporation of metal Se followed by depositing CdS layer and ZnO nanoparticle thin film coating to complete a solar cell fabrication. Structure, absorption spectrum, and photo-electricity conversion efficiency for the as-grown CIGS thin film solar cell are under study.

  18. Nanosphere lithography applied to magnetic thin films

    NASA Astrophysics Data System (ADS)

    Gleason, Russell

    Magnetic nanostructures have widespread applications in many areas of physics and engineering, and nanosphere lithography has recently emerged as promising tool for the fabrication of such nanostructures. The goal of this research is to explore the magnetic properties of a thin film of ferromagnetic material deposited onto a hexagonally close-packed monolayer array of polystyrene nanospheres, and how they differ from the magnetic properties of a typical flat thin film. The first portion of this research focuses on determining the optimum conditions for depositing a monolayer of nanospheres onto chemically pretreated silicon substrates (via drop-coating) and the subsequent characterization of the deposited nanosphere layer with scanning electron microscopy. Single layers of permalloy (Ni80Fe20) are then deposited on top of the nanosphere array via DC magnetron sputtering, resulting in a thin film array of magnetic nanocaps. The coercivities of the thin films are measured using a home-built magneto-optical Kerr effect (MOKE) system in longitudinal arrangement. MOKE measurements show that for a single layer of permalloy (Py), the coercivity of a thin film deposited onto an array of nanospheres increases compared to that of a flat thin film. In addition, the coercivity increases as the nanosphere size decreases for the same deposited layer. It is postulated that magnetic exchange decoupling between neighboring nanocaps suppresses the propagation of magnetic domain walls, and this pinning of the domain walls is thought to be the primary source of the increase in coercivity.

  19. Photophysical properties of Alq3 thin films

    NASA Astrophysics Data System (ADS)

    Zawadzka, A.; P?óciennik, P.; Strzelecki, J.; ?ukasiak, Z.; Sahraoui, B.

    2013-11-01

    This work contains investigation results of the photophysical properties of aluminum (III) tris(8-hydroxyquinoline) thin films. The Alq3 thin films were successfully fabricated by Physical Vapor Deposition technique. The films were grown on transparent: (quartz and glass) and semiconductor (n-type silica) substrates kept at room temperature during the deposition process. Selected films were annealed after fabrication in ambient atmosphere for 12 h at the temperature equal to 100 °C and 150 °C. Morphology of the films was investigated by AFM technique. Photophysical properties were characterized via photoluminescence, transmission, second and third harmonic generation measurements. The thin films exhibit high structural quality regardless of the annealing process, but the stability of the film can be improved by using an appropriate temperature during the annealing process. Photoluminescence of Alq3 films obtained in air were efficient and stable. The measurements of transmission, SHG and THG spectra allowed us to determine optical constant of the films. We find that the photophysical properties were strictly connected with the morphology and the annealing process significantly changes the structural properties of the films.

  20. Thin-Film Nanocapacitor and Its Characterization

    ERIC Educational Resources Information Center

    Hunter, David N.; Pickering, Shawn L.; Jia, Dongdong

    2007-01-01

    An undergraduate thin-film nanotechnology laboratory was designed. Nanocapacitors were fabricated on silicon substrates by sputter deposition. A mask was designed to form the shape of the capacitor and its electrodes. Thin metal layers of Au with a 80 nm thickness were deposited and used as two infinitely large parallel plates for a capacitor.…

  1. Thin films, asphaltenes, and reservoir wettability

    SciTech Connect

    Kaminsky, R.; Bergeron, V.; Radke, C.J. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Chemical Engineering

    1993-04-01

    Reservoir wettability impacts the success of oil recovery by waterflooding and other methods. To understand wettability and its alteration, thin-film forces in solid-aqueous-oil systems must be elucidated. Upon rupture of thick aqueous films separating the oil and rock phases, asphaltene components in the crude oil adsorb irreversibly on the solid surface, changing it from water-wet to oil-wet. Conditions of wettability alteration can be found by performing adhesion tests, in which an oil droplet is brought into contact with a solid surface. Exceeding a critical capillary pressure destabilizes the film, causing spontaneous film rupture to a molecularly adsorbed layer and oil adhesion accompanied by pinning at the three-phase contact line. The authors conduct adhesion experiments similar to those of Buckley and Morrow and simultaneously examine the state of the underlying thin film using optical microscopy and microinterferometry. Aqueous thin films between an asphaltic Orcutt crude oil and glass surfaces are studied as a function of aqueous pH and salinity. For the first time, they prove experimentally that strongly water-wet to strongly oil-wet wettability alteration and contact-angle pinning occur when thick aqueous films thin to molecularly adsorbed films and when the oil phase contains asphaltene molecules.

  2. Phase evolution in boron nitride thin films

    Microsoft Academic Search

    D. J. Kester; K. S. Ailey; R. F. Davis; K. L. More

    1993-01-01

    Boron nitride (BN) thin films were deposited on monocrystalline Si (100) wafers using electron beam evaporation of boron with simultaneous bombardment by nitrogen and argon ions. The effect of film thickness on the resultant BN phase was investigated using Fourier transform infrared (FTIR) spectroscopy and high resolution transmission electron microscopy (HRTEM). These techniques revealed the consecutive deposition of an initial

  3. Surface Plasmons in Thin Metallic Films

    E-print Network

    A. V. Latyshev; A. A. Yushkanov

    2010-10-11

    For the first time it is shown that for thin metallic films thickness of which not exceed thickness of skin -- layer, the problem of description of surface plasma oscillations allows analytical solution by arbitrary ratio between length of electrons free path and thickness of a film. The dependance of frequency surface plasma oscillations on wave number is carry out.

  4. Induced electronic anisotropy in bismuth thin films

    SciTech Connect

    Liao, Albert D., E-mail: aliao@mit.edu [Research Laboratory of Electronics, MIT, Cambridge, Massachusetts 02139 (United States); Yao, Mengliang; Opeil, Cyril [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Katmis, Ferhat; Moodera, Jagadeesh S. [Department of Physics, MIT, Cambridge, Massachusetts 02139 (United States); Li, Mingda [Department of Nuclear Science and Engineering, MIT, Cambridge, Massachusetts 02139 (United States); Tang, Shuang [Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts 02139 (United States); Dresselhaus, Mildred S. [Research Laboratory of Electronics, MIT, Cambridge, Massachusetts 02139 (United States); Department of Physics, MIT, Cambridge, Massachusetts 02139 (United States)

    2014-08-11

    We use magneto-resistance measurements to investigate the effect of texturing in polycrystalline bismuth thin films. Electrical current in bismuth films with texturing such that all grains are oriented with the trigonal axis normal to the film plane is found to flow in an isotropic manner. By contrast, bismuth films with no texture such that not all grains have the same crystallographic orientation exhibit anisotropic current flow, giving rise to preferential current flow pathways in each grain depending on its orientation. Extraction of the mobility and the phase coherence length in both types of films indicates that carrier scattering is not responsible for the observed anisotropic conduction. Evidence from control experiments on antimony thin films suggests that the anisotropy is a result of bismuth's large electron effective mass anisotropy.

  5. Study of iron mononitride thin films

    SciTech Connect

    Tayal, Akhil, E-mail: mgupta@csr.res.in; Gupta, Mukul, E-mail: mgupta@csr.res.in; Phase, D. M., E-mail: mgupta@csr.res.in; Reddy, V. R., E-mail: mgupta@csr.res.in; Gupta, Ajay, E-mail: mgupta@csr.res.in [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore,-452001 (India)

    2014-04-24

    In this work we have studied the crystal structural and local ordering of iron and nitrogen in iron mononitride thin films prepared using dc magnetron sputtering at sputtering power of 100W and 500W. The films were sputtered using pure nitrogen to enhance the reactivity of nitrogen with iron. The x-ray diffraction (XRD), conversion electron Mössbauer spectroscopy (CEMS) and soft x-ray absorption spectroscopy (SXAS) studies shows that the film crystallizes in ZnS-type crystal structure.

  6. Polysilicon Super-Thin-Film Transistor (SFT)

    Microsoft Academic Search

    Hisao Hayashi; Takashi Noguchi; Takefumi Oshima

    1984-01-01

    N-channel MOS FET's have been fabricated in super-thin polysilicon film on quartz substrate. The thickness of the film had an important role in improving the electrical properties. Moreover, grain boundary passivation by the hydrogen from a plasma-SiN film has been developed to increase the field effect mobility. The field effect mobility is more than 20 cm2\\/V\\\\cdots at the polysilicon thickness

  7. Flexible Thin Metal Film Thermal Sensing System

    NASA Technical Reports Server (NTRS)

    Thomsen, Donald Laurence (Inventor)

    2012-01-01

    A flexible thin metal film thermal sensing system is provided. A thermally-conductive film made from a thermally-insulating material is doped with thermally-conductive material. At least one layer of electrically-conductive metal is deposited directly onto a surface of the thermally-conductive film. One or more devices are coupled to the layer(s) to measure an electrical characteristic associated therewith as an indication of temperature.

  8. Spectroscopic Ellipsometry of Palladium Thin Films.

    NASA Astrophysics Data System (ADS)

    Sullivan, Brian Thomas

    Spectroscropic ellipsometry is a nondestructive, ambient surface analysis technique for studying surfaces, interfaces and thin films. To take advantage of this method an automatic spectroscopic ellipsometer was designed and constructed for the microstructural characterization of thin films. This high precision instrument is capable of measuring in real-time the optical properties of bulk or thin film materials over the visible-UV region (1.5 -6.0 eV). The microstructure of thin films can then be determined from an effective medium analysis of the spectroellipsometric data to investigate how the film morphology is influenced by the film preparation conditions. In this thesis the pseudodielectric function of palladium films prepared by dc planar magentron sputtering was measured while the substrate temperature, argon partial pressure and rf-induced substrate bias were varied independently during deposition. Through spectroellipsometry, the evolution of the microstructure of the films was correlated to the changing deposition environment. The film data are in excellent agreement with the effective medium theory of Sen, Scala, and Cohen, relevant for a random coated-particle microstructure where the grains are optically isolated from each other, and which had been previously applied to only rhodium films. A microstructural analysis indicated a general trend towards increased porosity and microroughness of the films with higher argon pressures and substrate temperatures. The films deposited above a transition pressure of 15 mTorr were best described optically by a random coated -particle microstructure and electron microscopy confirmed the isolation of grains by void boundaries. With increasing rf-induced substrate biasing, the Pd film microstructure was modified in a manner similar to that obtained by varying the substrate temperature alone. The measured deposition rate while bias sputtering was significantly higher than that expected based upon the measured resputtering rate and several mechanisms were proposed to account for the enhancement in the deposition rate. The films were best characterized by a 2-dimensional isotropy which was supported by the columnar nature of the films observed by electron microscopy. Finally, the dielectric function of the "best" palladium film was compared to optical constants of Pd previously reported in the literature for bulk and thin film specimens.

  9. Bistability in a Superconducting Al Thin Film Induced by Arrays of Fe-Nanodot Magnetic Vortices

    NASA Astrophysics Data System (ADS)

    Villegas, J. E.; Li, C.-P.; Schuller, Ivan K.

    2007-11-01

    A hybrid system, consisting of an array of Fe nanodots covered by a superconducting Al thin film, exhibits very unusual magnetotransport, including a giant hysteretic magnetoresistance with different reversible or irreversible regimes related to the magnetic state of the array. These effects originate from the magnetic fields produced by magnetic nanodots in the “magnetic vortex state.” This is a unique model system in which properties of a magnetic array are transferred into the superconductor.

  10. Infrared transparent carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Hu, Liangbing; Hecht, David S.; Grüner, George

    2009-02-01

    We have measured the infrared properties of optically transparent and electrically conductive single walled carbon nanotube thin films. We found that nanotube films with sheet resistance values of 200 ?/sq show outstanding transmittance in the infrared range up to at least 22 ?m, with an average transmittance greater than 90% over this range. The infrared properties of various materials were compared and we found that transparent nanotube electrodes and transparent graphene electrodes outperform the others in several key categories. This study opens another important application area for conductive nanotube thin films.

  11. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G. (Cutchogue, NY)

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  12. Ambient pressure process for preparing aerogel thin films reliquified sols useful in preparing aerogel thin films

    DOEpatents

    Brinker, Charles Jeffrey (Albuquerque, NM); Prakash, Sai Sivasankaran (Minneapolis, MN)

    1999-01-01

    A method for preparing aerogel thin films by an ambient-pressure, continuous process. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.

  13. Method for making thin polypropylene film

    DOEpatents

    Behymer, R.D.; Scholten, J.A.

    1985-11-21

    An economical method is provided for making uniform thickness polypropylene film as thin as 100 Angstroms. A solution of polypropylene dissolved in xylene is formed by mixing granular polypropylene and xylene together in a flask at an elevated temperature. A substrate, such as a glass plate or microscope slide is immersed in the solution. When the glass plate is withdrawn from the solution at a uniform rate, a thin polypropylene film forms on a flat surface area of the glass plate as the result of xylene evaporation. The actual thickness of the polypropylene film is functional of the polypropylene in xylene solution concentration, and the particular withdrawal rate of the glass plate from the solution. After formation, the thin polypropylene film is floated from the glass plate onto the surface of water, from which it is picked up with a wire hoop.

  14. Magnetoelectric thin film composites with interdigital electrodes

    NASA Astrophysics Data System (ADS)

    Piorra, A.; Jahns, R.; Teliban, I.; Gugat, J. L.; Gerken, M.; Knöchel, R.; Quandt, E.

    2013-07-01

    Magnetoelectric (ME) thin film composites on silicon cantilevers are fabricated using Pb(Zr0.52Ti0.45)O3 (PZT) films with interdigital transducer electrodes on the top side and FeCoSiB amorphous magnetostrictive thin films on the backside. These composites without any direct interface between the piezoelectric and magnetostrictive phase are superior to conventional plate capacitor-type thin film ME composites. A limit of detection of 2.6 pT/Hz1/2 at the mechanical resonance is determined which corresponds to an improvement of a factor of approximately 2.8 compared to the best plate type sensor using AlN as the piezoelectric phase and even a factor of approximately 4 for a PZT plate capacitor.

  15. Tungsten-doped thin film materials

    DOEpatents

    Xiang, Xiao-Dong; Chang, Hauyee; Gao, Chen; Takeuchi, Ichiro; Schultz, Peter G.

    2003-12-09

    A dielectric thin film material for high frequency use, including use as a capacitor, and having a low dielectric loss factor is provided, the film comprising a composition of tungsten-doped barium strontium titanate of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3, where X is between about 0.5 and about 1.0. Also provided is a method for making a dielectric thin film of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3 and doped with W, where X is between about 0.5 and about 1.0, a substrate is provided, TiO.sub.2, the W dopant, Ba, and optionally Sr are deposited on the substrate, and the substrate containing TiO.sub.2, the W dopant, Ba, and optionally Sr is heated to form a low loss dielectric thin film.

  16. NANO-INDENTATION OF COPPER THIN FILMS ON SILICON SUBSTRATES

    E-print Network

    Suresh, Subra

    NANO-INDENTATION OF COPPER THIN FILMS ON SILICON SUBSTRATES S. Suresh1 , T.-G. Nieh2 and B.W. Choi2: Mechanical properties; Nano-indentation; Thin films; Copper; Dislocations Introduction Indentation methods films on substrates (e.g., [2,3]) using instrumented indentation. Nano-indentation studies of thin films

  17. LPG sensing performance of nanostructured zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Bari, A. R.; Patil, L. A.

    2013-06-01

    Nanostructured zinc oxide thin films were prepared using ultrasonic spray pyrolysis technique. Zinc acetate was used as a starting precursor. As prepared thin films were characterized using different analytical techniques. The sensing performance of the nanostructured zinc oxide thin films was studied on exposure of various gases. The films were observed to be most sensitive (S= 1727) to LPG at 300°C.

  18. Thermal conductivities of thin, sputtered optical films

    NASA Astrophysics Data System (ADS)

    Henager, C. H., Jr.; Pawlewicz, W. T.

    1993-01-01

    The normal component of thin-film thermal conductivity has been measured for several advanced sputtered optical materials. Included are data for single layers of boron nitride, silicon aluminum nitride, silicon aluminum oxynitride, silicon carbide, and for dielectric-enhanced metal reflectors of the form Al(SiO2/Si3N4)super n and Al(Al2O3/AlN)super n. Sputtered films of more conventional materials such as SiO2, Al2O3, Ta2O5, Ti, and Si have also been measured. The data show that thin-film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film-substrate interface contribution is presented.

  19. Electrochemical Analysis of Conducting Polymer Thin Films

    PubMed Central

    Vyas, Ritesh N.; Wang, Bin

    2010-01-01

    Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene) (PPV), in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values. PMID:20480052

  20. X-ray diffraction characterization of thin superconductive films

    Microsoft Academic Search

    K. J. Kozaczek; T. R. Watkins; W. B. Carter

    1995-01-01

    The physical and mechanical properties of thin films are often different from the properties of bulk material and are dictated by the film\\/substrate orientation relationship, crystal anisotropy and crystalgraphic texture of the film. X-ray diffraction texture analysis provides information about preferential film growth and can be used for optimization of deposition parameters and prediction of properties of thin films. An

  1. Critical currents of ion-beam sputtered amorphous beryllium thin films and their application to an Abrikosov vortex memory

    SciTech Connect

    Okamoto, M.; Takei, K.; Kubo, S.; Mukaida, M.; Miyahara, K.

    1987-07-01

    Critical current and flux pinning were examined for ion-beam sputtered (IBS)= amorphous beryllium (a-Be) thin films with T/sub c/ 6 K. Pinning forces in IBS a-Be films were one or more than one order of magnitude smaller than those for crystalline superconductors, but were still rather large for amorphous superconductors. The viscosity coefficient for IBS a-Be was very small, 1--2 x 10/sup -9/ N s/m/sup 2/, which was only a few tenths as large as viscosity coefficients for other metallic superconductors. Write operation characteristics for Abrikosov vortex memory with an IBS a-Be vortex storage region was tested. The write current level was reduced to about two thirds of that for fine-grained PbInAu previously reported. IBS a-Be films were proved to be a potential material for use in an Abrikosov vortex memory.

  2. Thin film dielectric composite materials

    DOEpatents

    Jia, Quanxi (Los Alamos, NM); Gibbons, Brady J. (Los Alamos, NM); Findikoglu, Alp T. (Los Alamos, NM); Park, Bae Ho (Los Alamos, NM)

    2002-01-01

    A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

  3. Thin Film Transistors On Plastic Substrates

    DOEpatents

    Carey, Paul G. (Mountain View, CA); Smith, Patrick M. (San Ramon, CA); Sigmon, Thomas W. (Portola Valley, CA); Aceves, Randy C. (Livermore, CA)

    2004-01-20

    A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The silicon based thin film transistor produced by the process includes a low temperature substrate incapable of withstanding sustained processing temperatures greater than about 250.degree. C., an insulating layer on the substrate, a layer of silicon on the insulating layer having sections of doped silicon, undoped silicon, and poly-silicon, a gate dielectric layer on the layer of silicon, a layer of gate metal on the dielectric layer, a layer of oxide on sections of the layer of silicon and the layer of gate metal, and metal contacts on sections of the layer of silicon and layer of gate metal defining source, gate, and drain contacts, and interconnects.

  4. Vibration welding system with thin film sensor

    DOEpatents

    Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

    2014-03-18

    A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

  5. Thin film high temperature silicide thermocouples

    NASA Astrophysics Data System (ADS)

    Kreider, Ken

    Sputter-deposited TiSi2, MoSi2, WSi2, and TaSi2 thin films were investigated for use as thermoelements, and the results are reported. The performance and stability of the films at temperatures up to 1200 C are reported. The results demonstrate the feasibility of using the TiSi2 and MoSi2 on Al2O3 substrates as thin film thermocouples. The thermoelectric output is stable at temperatures as high as 1200 C. The Seebeck coefficient is not diminished by loss of material since thermoelectric voltage is not a function of film thickness. This outstanding corrosion resistance may lead to numerous applications where metal thermocouples are vulnerable to deterioration.

  6. Transport in Topological Insulator Thin Films

    NASA Astrophysics Data System (ADS)

    Fatemi, Valla; Steinberg, Hadar; Laloe, Jean-Baptiste; Katmis, Ferhat; Orona, Lucas; Moodera, Jagadeesh; Jarillo-Herrero, Pablo

    2012-02-01

    We report on electronic transport measurements on Bi2Se3 thin-film devices and show that an ambipolar modulation can be achieved via the electric field effect by using a top-gate with a high-k dielectric insulator. By analyzing the evolution of the weak anti-localization magnetoconductance behavior with respect to gate voltage and temperature, we find that we are able to modulate the effective number of channels, demonstrating that the coherent coupling between the surface and the bulk is tunable. Moreover, we investigate the formation and behavior of tunable p-n junctions on thin-film devices with multiple local top-gates.

  7. Emittance Theory for Thin Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

    1994-01-01

    Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

  8. Thin-film resistor array characterization

    NASA Astrophysics Data System (ADS)

    Sanderford, Vicki; Mobley, Scott

    1994-12-01

    This paper provides the results of thin-film resistor array testing which was recently performed at the System Simulation and Development Directorate (SS&DD), Research, Development, and Engineering Center (RDEC). The objective of these tests was to determine the suitability of the Australian thin-film resistor technology for use as a key component in an Infrared Scene Projector (IRSP) for Hardware-in-the-Loop (HWIL) simulations involving systems which utilize linear rows of detectors. The tests were configured to measure spatial uniformity, temporal response, dynamic range, and relative energy output as a function of power input. D65O funding was used to purchase the resistor arrays.

  9. Feasibility Study of Thin Film Thermocouple Piles

    NASA Technical Reports Server (NTRS)

    Sisk, R. C.

    2001-01-01

    Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

  10. Micro-sensor thin-film anemometer

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark (Inventor); McGinley, Catherine B. (Inventor); Spina, Eric F. (Inventor); Stephens, Ralph M. (Inventor); Hopson, Jr., Purnell (Inventor); Cruz, Vincent B. (Inventor)

    1996-01-01

    A device for measuring turbulence in high-speed flows is provided which includes a micro-sensor thin-film probe. The probe is formed from a single crystal of aluminum oxide having a 14.degree. half-wedge shaped portion. The tip of the half-wedge is rounded and has a thin-film sensor attached along the stagnation line. The bottom surface of the half-wedge is tilted upward to relieve shock induced disturbances created by the curved tip of the half-wedge. The sensor is applied using a microphotolithography technique.

  11. Characterizations of high resistivity TiNxOy thin films for applications in thin film resistors

    Microsoft Academic Search

    Nguyen Duy Cuong; Dong-Jin Kim; Byoung-Don Kang; Chang Soo Kim; Soon-Gil Yoon

    2007-01-01

    We report about developing high resistivity thin film resistors using titanium oxy-nitride. Titanium nitride films of different thicknesses ranging from 50 to 300nm were deposited on SiO2\\/Si substrates using the reactive magnetron sputtering method. After deposition, these films were annealed in the air ambient. The structural and electrical properties of the films were examined as a function of annealing temperature.

  12. The interplay between spatially separated ferromagnetic and superconducting thin films

    E-print Network

    Sullivan, Isaac John

    2013-02-22

    Ferromagnetic thin films have been grown via physical vapor deposition utilizing the technique of flash evaporation and characterized by measuring magnetization as a function of magnetic field. An Al thin film was evaporated atop the ferromagnetic...

  13. Dynamics and stability of thin liquid films

    NASA Astrophysics Data System (ADS)

    Craster, R. V.; Matar, O. K.

    2009-07-01

    The dynamics and stability of thin liquid films have fascinated scientists over many decades: the observations of regular wave patterns in film flows down a windowpane or along guttering, the patterning of dewetting droplets, and the fingering of viscous flows down a slope are all examples that are familiar in daily life. Thin film flows occur over a wide range of length scales and are central to numerous areas of engineering, geophysics, and biophysics; these include nanofluidics and microfluidics, coating flows, intensive processing, lava flows, dynamics of continental ice sheets, tear-film rupture, and surfactant replacement therapy. These flows have attracted considerable attention in the literature, which have resulted in many significant developments in experimental, analytical, and numerical research in this area. These include advances in understanding dewetting, thermocapillary- and surfactant-driven films, falling films and films flowing over structured, compliant, and rapidly rotating substrates, and evaporating films as well as those manipulated via use of electric fields to produce nanoscale patterns. These developments are reviewed in this paper and open problems and exciting research avenues in this thriving area of fluid mechanics are also highlighted.

  14. Perovskite thin films via atomic layer deposition.

    PubMed

    Sutherland, Brandon R; Hoogland, Sjoerd; Adachi, Michael M; Kanjanaboos, Pongsakorn; Wong, Chris T O; McDowell, Jeffrey J; Xu, Jixian; Voznyy, Oleksandr; Ning, Zhijun; Houtepen, Arjan J; Sargent, Edward H

    2015-01-01

    A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3 NH3 PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm(-1) . PMID:25359103

  15. Superconducting thin films on potassium tantalate substrates

    DOEpatents

    Feenstra, Roeland (Oak Ridge, TN); Boatner, Lynn A. (Oak Ridge, TN)

    1992-01-01

    A superconductive system for the lossless transmission of electrical current comprising a thin film of superconducting material Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x epitaxially deposited upon a KTaO.sub.3 substrate. The KTaO.sub.3 is an improved substrate over those of the prior art since the it exhibits small lattice constant mismatch and does not chemically react with the superconducting film.

  16. Annealed CVD molybdenum thin film surface

    DOEpatents

    Carver, Gary E. (Tucson, AZ); Seraphin, Bernhard O. (Tucson, AZ)

    1984-01-01

    Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.

  17. Micropatterned lead zirconium titanate thin films

    Microsoft Academic Search

    M. Ozenbas

    Micropatterning of Pb(Zr0.52Ti0.48)O3 (PZT) thin films with line features as small as 350 nm was demonstrated through capillary molding of organometallic solutions within the continuous channels of an elastomeric mold. Despite the large stresses that develop during the evaporation of the solvent, pyrolysis of the organics, and the densification and crystallization of the inorganic gel, the patterned crystalline PZT films

  18. Sol-gel derived ?-BBO thin film

    NASA Astrophysics Data System (ADS)

    Nie, Wenjiang; Lurin, Christian L.; Paz-Pujalt, Gustavo R.

    1992-12-01

    (beta) -BaB2O4((beta) -BBO) is known as one of the best inorganic nonlinear crystals. It is now widely used for frequency doubling, frequency mixing in the UV range and optical parametric oscillation in the UV and near infrared regions. To put this material into thin film form would make it very attractive for integrated optical devices. Vacuum deposition techniques are not suitable for the fabrication of borates thin films due to the difficult evaporation or sputtering of oxides based on light elements. The low processing temperature of the sol-gel method allows the formation of stoichiometric and expected oxygen coordination of BaB2O4 in liquid phase. (beta) -BBO thin films has been successfully prepared by the sol-gel method through hydrolysis of barium and boron alkoxides. The accomplishment of hydrolysis is found to be essential for the removal of residual organic at high temperatures. The choice of precursors, hydrolysis ratio, and thermal treatments have critical influences on the formation, the morphology and the nucleation of (beta) -BBO phase of the film. The undesirable interaction between the film and the substrate limits the formation of (beta) -BBO polycrystalline film to only a few selected substrates.

  19. Numerical simulation of laser-induced thin film delamination

    Microsoft Academic Search

    Yueming Liang; Xiaopeng Bi; Junlan Wang

    2008-01-01

    Laser-induced thin film spallation has been developed to be one of the most powerful tools for quantitative measurement of thin film interfacial adhesion. High-energy laser pulse absorption generates stress pulse that can be used to delaminate a thin film–substrate interface. Interfacial strength is obtained from the measured surface motion of the thin film using elastic wave mechanics. Due to the

  20. Effective modulus of heterogeneous materials in thin film configurations

    Microsoft Academic Search

    X. M. Xie; H. Fan

    2010-01-01

    Thin film is one of the important geometric configurations in the microelectronic devices. The traditional theories for heterogeneous material are challenged for their application to the thin film configurations (the free-standing and substrate-attached thin films). In the present paper, a finite element analysis with a statistic procedure is proposed to estimate the effective properties of thin films. For the free-standing

  1. Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films

    SciTech Connect

    Hellman, Frances

    1998-10-03

    OAK B204 Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films. The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and hTi-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials.

  2. Microwave complex conductivity of the YBCO thin films as a function of static external magnetic field

    NASA Astrophysics Data System (ADS)

    Krupka, J.; Judek, J.; Jastrzebski, C.; Ciuk, T.; Wosik, J.; Zdrojek, M.

    2014-03-01

    A sapphire rod resonator operating at microwave frequencies was used to determine the electric properties of 600 nm thick YBCO films in the superconducting state. The rigorous electromagnetic modelling was applied to transform the measured Q-factor and the resonant frequency to the complex conductivity of high accuracy, which was previously shown to describe the intrinsic properties of superconductor thin films in more precise manner than the complex impedance. Static external magnetic field induces typical transition to normal state due to introduction of magnetic vortices into the sample. Observed magnetic hysteresis has the origin in the strong temperature dependent pinning. Additional energy absorption at about 1.5 T was observed.

  3. VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS*

    E-print Network

    ERL 03-8 VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS* Yulin Li# and Simon Ho performance of Titanium- Zirconium-Vanadium (TiZrV) NEG thin films was investigated to provide `engineering- Zirconium-Vanadium (TiZrV) NEG thin films, deposited on the interior of stainless steel (SST) pipes. The Ti

  4. Growth induced magnetic anisotropy in crystalline and amorphous thin films

    SciTech Connect

    Hellman, F.

    1998-07-20

    The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and Ni-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials. A brief summary of work done in each area is given.

  5. Cd x Zn 1? x S solid solution thin films, CdS thin films and CdS\\/ZnS multilayer thin films grown by SILAR technique

    Microsoft Academic Search

    Mika P. Valkonen; Seppo Lindroos; Markku Leskelä

    1998-01-01

    CdxZn1?xS solid solution thin films were grown by successive ionic layer adsorption and reaction (SILAR) technique on soda lime glass, ITO-covered glass and polymer substrates. In addition, CdS thin films and CdS\\/ZnS multilayer thin films were deposited on polymer substrates. The thin films were characterized by X-ray diffraction and energy dispersive X-ray analysis. The CdxZn1?xS films were polycrystalline and cubic

  6. Surface Plasmon Waves on Thin Metal Films.

    NASA Astrophysics Data System (ADS)

    Craig, Alan Ellsworth

    Surface-plasmon polaritons propagating on thin metal films bounded by dielectrics of nearly equal refractive indexes comprise two bound modes. Calculations indicate that, while the modes are degenerate on thick films, both the real and the imaginary components of the propagation constants for the modes split into two branches on successively thinner films. Considering these non-degenerate modes, the mode exhibiting a symmetric (antisymmetric) transverse profile of the longitudinally polarized electric field component, has propagation constant components both of which increase (decrease) with decreasing film thickness. Theoretical propagation constant eigenvalue (PCE) curves have been plotted which delineate this dependence of both propagation constant components on film thickness. By means of a retroreflecting, hemispherical glass coupler in an attenuated total reflection (ATR) configuration, light of wavelength 632.8 nm coupled to the modes of thin silver films deposited on polished glass substrates. Lorentzian lineshape dips in the plots of reflectance vs. angle of incidence indicate the presence of the plasmon modes. The real and imaginary components of the propagation constraints (i.e., the propagation constant and loss coefficient) were calculated from the angular positions and widths of the ATR resonances recorded. Films of several thicknesses were probed. Results which support the theoretically predicted curves were reported.

  7. Unabridged phase diagram for single-phased FeSexTe1-x thin films

    PubMed Central

    Zhuang, Jincheng; Yeoh, Wai Kong; Cui, Xiangyuan; Xu, Xun; Du, Yi; Shi, Zhixiang; Ringer, Simon P.; Wang, Xiaolin; Dou, Shi Xue

    2014-01-01

    A complete phase diagram and its corresponding physical properties are essential prerequisites to understand the underlying mechanism of iron-based superconductivity. For the structurally simplest 11 (FeSeTe) system, earlier attempts using bulk samples have not been able to do so due to the fabrication difficulties. Here, thin FeSexTe1-x films with the Se content covering the full range (0 ? x ? 1) were fabricated by using pulsed laser deposition method. Crystal structure analysis shows that all films retain the tetragonal structure in room temperature. Significantly, the highest superconducting transition temperature (TC = 20?K) occurs in the newly discovered domain, i.e., 0.6 ? x ? 0.8. The single-phased superconducting dome for the full Se doping range is the first of its kind in iron chalcogenide superconductors. Our results present a new avenue to explore novel physics as well as to optimize superconductors. PMID:25449669

  8. Unabridged phase diagram for single-phased FeSexTe1-x thin films

    NASA Astrophysics Data System (ADS)

    Zhuang, Jincheng; Yeoh, Wai Kong; Cui, Xiangyuan; Xu, Xun; Du, Yi; Shi, Zhixiang; Ringer, Simon P.; Wang, Xiaolin; Dou, Shi Xue

    2014-12-01

    A complete phase diagram and its corresponding physical properties are essential prerequisites to understand the underlying mechanism of iron-based superconductivity. For the structurally simplest 11 (FeSeTe) system, earlier attempts using bulk samples have not been able to do so due to the fabrication difficulties. Here, thin FeSexTe1-x films with the Se content covering the full range (0 <= x <= 1) were fabricated by using pulsed laser deposition method. Crystal structure analysis shows that all films retain the tetragonal structure in room temperature. Significantly, the highest superconducting transition temperature (TC = 20 K) occurs in the newly discovered domain, i.e., 0.6 <= x <= 0.8. The single-phased superconducting dome for the full Se doping range is the first of its kind in iron chalcogenide superconductors. Our results present a new avenue to explore novel physics as well as to optimize superconductors.

  9. Unabridged phase diagram for single-phased FeSe(x)Te(1-x) thin films.

    PubMed

    Zhuang, Jincheng; Yeoh, Wai Kong; Cui, Xiangyuan; Xu, Xun; Du, Yi; Shi, Zhixiang; Ringer, Simon P; Wang, Xiaolin; Dou, Shi Xue

    2014-01-01

    A complete phase diagram and its corresponding physical properties are essential prerequisites to understand the underlying mechanism of iron-based superconductivity. For the structurally simplest 11 (FeSeTe) system, earlier attempts using bulk samples have not been able to do so due to the fabrication difficulties. Here, thin FeSe(x)Te(1-x) films with the Se content covering the full range (0 ? x ? 1) were fabricated by using pulsed laser deposition method. Crystal structure analysis shows that all films retain the tetragonal structure in room temperature. Significantly, the highest superconducting transition temperature (T(C) = 20 K) occurs in the newly discovered domain, i.e., 0.6 ? x ? 0.8. The single-phased superconducting dome for the full Se doping range is the first of its kind in iron chalcogenide superconductors. Our results present a new avenue to explore novel physics as well as to optimize superconductors. PMID:25449669

  10. Rim instability of bursting thin smectic films

    NASA Astrophysics Data System (ADS)

    Trittel, Torsten; John, Thomas; Tsuji, Kinko; Stannarius, Ralf

    2013-05-01

    The rupture of thin smectic bubbles is studied by means of high speed video imaging. Bubbles of centimeter diameter and film thicknesses in the nanometer range are pierced, and the instabilities of the moving rim around the opening hole are described. Scaling laws describe the relation between film thickness and features of the filamentation process of the rim. A flapping motion of the retracting smectic film is assumed as the origin of the observed filamentation instability. A comparison with similar phenomena in soap bubbles is made. The present experiments extend studies on soap films [H. Lhuissier and E. Villermaux, Phys. Rev. Lett. 103, 054501 (2009), 10.1103/PhysRevLett.103.054501] to much thinner, uniform films of thermotropic liquid crystals.

  11. Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films

    NASA Technical Reports Server (NTRS)

    Schoenhuber, P.; Moon, F. C.

    1995-01-01

    Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation forces, e.g. microgravity - magnetic damping devices.

  12. PLD growth of thin film Zinc Phosphide

    NASA Astrophysics Data System (ADS)

    Vaddi, Rajesh; Vasekar, Parag; Westgate, Charles; White, Bruce

    2013-03-01

    The development of efficient, low cost solar cells to meet society's growing energy needs has triggered tremendous interest in developing photovoltaics formed from earth abundant materials. Zinc phosphide (Zn3P2) is a promising earth abundant absorber layer for photovoltaic energy conversion with a nearly ideal band gap (1.5eV) and a large absorption coefficient of 10^4/cm. In this work we examine the growth parameters, electrical and optical properties of thin film zinc phosphide produced using pulsed laser deposition (PLD) from a zinc phosphide target at laser fluencies ranging from 1-3 J/cm2. For the laser fluences explored, highly resistive amorphous zinc phosphide thin films were produced with a band gap of approximately 1.7 eV. The thin films could be transformed from amorphous to polycrystalline zinc phosphide by annealing at 400C for 15mins in a N2 atmosphere. High resolution X-ray photoelectron spectroscopy (XPS) is used to examine the binding energies of Zn 2p3/2 and Phosphorous 2p3/2 signals and are in the range of 1021.6 eV and 127.5 eV. Energy Dispersive X-ray Spectroscopy (EDAX) revealed that the Zn3P2 thin films are nearly stoichiometric in composition. Hall mobility in these materials and Zn3P2/ZnS hetrojunction solar cell performance will be discussed.

  13. Synthesis of thin molecular sieve films

    Microsoft Academic Search

    J. Hedlund; J. Sterte

    1999-01-01

    A method to synthesize thin films of various molecular sieves on a number of substrates employing pre-seeding has been developed. The substrate is modified to enable adsorption of seed crystals. Substrates with an originally negative surface charge are charge reversed by adsorption of cationic polymer molecules. Nobel metal substrates are first silanized to obtain a negative surface charge. Nano seed

  14. Thin film hydrous metal oxide catalysts

    DOEpatents

    Dosch, Robert G. (Albuquerque, NM); Stephens, Howard P. (Albuquerque, NM)

    1995-01-01

    Thin film (<100 nm) hydrous metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

  15. Thin-Film Solid Oxide Fuel Cells

    NASA Technical Reports Server (NTRS)

    Chen, Xin; Wu, Nai-Juan; Ignatiev, Alex

    2009-01-01

    The development of thin-film solid oxide fuel cells (TFSOFCs) and a method of fabricating them have progressed to the prototype stage. This can result in the reduction of mass, volume, and the cost of materials for a given power level.

  16. Integrated thin film fluorescence NOx sensor concept

    Microsoft Academic Search

    Margaret L. Tuma; Russell W. Gruhlke

    1997-01-01

    A fluorescence sensor system is proposed that integrates emission and detection methods as well as optical and electronic components in a thin film geometry. Predicted properties of this sensor include: increased sensitivity, shielding form unwanted radiation, wavelength filtering, potential operation at high temperatures, and miniaturization. The sensor can be tuned to measure a wide variety of species by varying its

  17. Instability of Viscoelastic Thin Films, and Applications

    Microsoft Academic Search

    Scott Norris; Michael Aziz; Michael Brenner

    2009-01-01

    An ion beam bombarding a solid surface has been long been known to produce an instability leading to a modulated surface (with ripples or dots); though the basic mechanisms for this instability remain under considerable debate. During our investigation of this problem, we have been led to a basic problem in thin film fluid mechanics: the instability of a viscoelastic

  18. Thin film thermocouples for internal combustion engines

    Microsoft Academic Search

    Kenneth G. Kreider

    1986-01-01

    The feasibility of fabricating thin film thermocouples on internal combustion engine hardware was investigated. The goal was to find a procedure that would be useful for the measurement of the surface metal temperature of valves, valve seats, combustion chamber surfaces, cylinder walls, and piston heads during engine operation. The approach pursued was to coat the engine hardware material with an

  19. Analysis of hydrogen isotopes in thin films

    Microsoft Academic Search

    T. K. Mehrhoff; J. O. Humphries

    1976-01-01

    Mass spectrometer modifications made for high resolution analysis of hydrogen isotopes outgassed from occluder thin films are described. The electronic modifications made to the source, magnet power supply, and scanning circuits provided increased precision in the mass range 2 to 6. Routine analyses were made at a resolution of 1300 with a Faraday cup detector. Extensive modification of the inlet

  20. Anemometer with hot platinum thin film

    Microsoft Academic Search

    F Mailly; A Giani; R Bonnot; P Temple-Boyer; F Pascal-Delannoy; A Foucaran; A Boyer

    2001-01-01

    The techniques of micromachining silicon are used for the manufacture of an anemometer with low electric consumption and great sensitivity. To reduce the energy consumption, a suspended membrane of silicon rich silicon nitride SiNx makes it possible to carry out the heat insulation between the heater and the substrate. Platinum (Pt) thin film (3000Å) with titanium (300Å) adhesion layer on

  1. Flexoelectricity in barium strontium titanate thin film

    NASA Astrophysics Data System (ADS)

    Kwon, Seol Ryung; Huang, Wenbin; Shu, Longlong; Yuan, Fuh-Gwo; Maria, Jon-Paul; Jiang, Xiaoning

    2014-10-01

    Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop flexoelectric devices on micro/nano scales due to the inherent scaling effect of flexoelectric effect. Ba0.7Sr0.3TiO3 thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The flexoelectric coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse flexoelectric coefficient of 24.5 ?C/m at Curie temperature (˜28 °C) and 17.44 ?C/m at 41 °C. The measured flexoelectric coefficients are comparable to that of bulk BST ceramics, which are reported to be 10-100 ?C/m. This result suggests that the flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.

  2. Electrolyte and Electrode Passivation for Thin Film Batteries

    NASA Technical Reports Server (NTRS)

    West, W.; Whitacre, J.; Ratnakumar, B.; Brandon, E.; Blosiu, J.; Surampudi, S.

    2000-01-01

    Passivation films for thin film batteries have been prepared and the conductivity and voltage stability window have been measured. Thin films of Li2CO3 have a large voltage stability window of 4.8V, which facilitates the use of this film as a passivation at both the lithium anode-electrolyte interface at high cathodic potentials.

  3. WO 3 sputtered thin films for NO x monitoring

    Microsoft Academic Search

    G. Sberveglieri; L. Depero; S. Groppelli; P. Nelli

    1995-01-01

    We present in this paper preliminary results concerning the preparation of tungsten trioxide thin films by reactive sputtering, the characterization either of their structural properties by means of XRD measurements or of the film morphology with the AFM microscope and the electrical response of the film towards toxic and pollutant gases. WO3 thin films showed a good sensitivity towards low

  4. Fracture of nanoporous thin-film glasses.

    PubMed

    Guyer, Eric P; Dauskardt, Reinhold H

    2004-01-01

    Fracture of nanoporous thin-film glasses is a significant challenge for the integration of these mechanically fragile materials in emerging microelectronic and biological technologies. In particular, the integration of these materials has been limited by accelerated cracking rates in moist environments leading to premature failure. Here, we demonstrate how cracking is affected by aqueous solution chemistry, and reveal anomalously high crack-growth rates in hydrogen peroxide solutions frequently encountered during device processing or when in use. Kinetic mechanisms involving the transport and steric hindrance of reactive hydrogen peroxide molecules at the crack tip are proposed. Thin-film design strategies that involve energy dissipation by local plasticity in thin ductile layers on increasing the resistance to cracking of nanoporous glass layers is demonstrated. Understanding how aqueous solutions influence cracking and associated device reliability is a fundamental challenge for these promising materials to be viable candidates for new technologies. PMID:14661017

  5. Thin-film semiconductor rectifier has improved properties

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Cadmium selenide-zinc selenide film is used as a thin film semiconductor rectifier. The film is vapor-deposited in a controlled concentration gradient into a glass substrate to form the required junctions between vapor-deposited gold electrodes.

  6. Z .Thin Solid Films 322 1998 913 The growth of hexagonal boron nitride thin films on silicon using single

    E-print Network

    Boo, Jin-Hyo

    Z .Thin Solid Films 322 1998 9­13 The growth of hexagonal boron nitride thin films on silicon using October 1997 Abstract Poylcrystalline hexagonal boron nitride thin films were deposited on silicon. Introduction Boron nitride has received considerable attention due to w xits exceptional properties 1

  7. Thin film multiferroic nanocomposites by ion implantation.

    PubMed

    Algueró, Miguel; Ricote, Jesús; Torres, María; Amorín, Harvey; Alberca, Aurora; Iglesias-Freire, Oscar; Nemes, Norbert; Holgado, Susana; Cervera, Manuel; Piqueras, Juan; Asenjo, Agustina; García-Hernández, Mar

    2014-02-12

    Thin film multiferroic nanocomposites might enable a range of potentially disruptive integrated magnetoelectric devices for information storage, spintronics, microwave telecommunications, and magnetic sensing. With this aim, we have investigated ion implantation of magnetic species into ferroelectric single crystal targets as a radically novel approach to prepare film nanoparticulate magnetic-metal ferroelectric-oxide composites. These materials are an alternative to multiferroic oxide epitaxial columnar nanostructures that are under intensive research, but whose magnetoelectric response is far from expectations. Here, we unambiguously demonstrate the preparation of such a thin film multiferroic nanocomposite of Co and BaTiO3 by ion implantation of a high dose of the magnetic species, followed by rapid thermal processing under tailored conditions. Results thus constitute a proof of concept for the feasibility of obtaining the materials by this alternative approach. Ion implantation is a standard technique for the microelectronic industry in combination with well-established patterning procedures. PMID:24417708

  8. Nanoindentation of GaSe thin films

    PubMed Central

    2012-01-01

    The structural and nanomechanical properties of GaSe thin films were investigated by means of X-ray diffraction (XRD) and nanoindentation techniques. The GaSe thin films were deposited on Si(111) substrates by pulsed laser deposition. XRD patterns reveal only the pure (000?l)-oriented reflections originating from the hexagonal GaSe phase and no trace of any impurity or additional phases. Nanoindentation results exhibit discontinuities (so-called multiple ‘pop-in’ events) in the loading segments of the load–displacement curves, and the continuous stiffness measurements indicate that the hardness and Young’s modulus of the hexagonal GaSe films are 1.8?±?0.2 and 65.8?±?5.6?GPa, respectively. PMID:22804961

  9. Nanoindentation of GaSe thin films

    NASA Astrophysics Data System (ADS)

    Jian, Sheng-Rui; Ku, Shin-An; Luo, Chih-Wei; Juang, Jenh-Yih

    2012-07-01

    The structural and nanomechanical properties of GaSe thin films were investigated by means of X-ray diffraction (XRD) and nanoindentation techniques. The GaSe thin films were deposited on Si(111) substrates by pulsed laser deposition. XRD patterns reveal only the pure (000 l)-oriented reflections originating from the hexagonal GaSe phase and no trace of any impurity or additional phases. Nanoindentation results exhibit discontinuities (so-called multiple `pop-in' events) in the loading segments of the load-displacement curves, and the continuous stiffness measurements indicate that the hardness and Young's modulus of the hexagonal GaSe films are 1.8 ± 0.2 and 65.8 ± 5.6 GPa, respectively.

  10. MISSE 5 Thin Films Space Exposure Experiment

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.; Kinard, William H.; Jones, James L.

    2007-01-01

    The Materials International Space Station Experiment (MISSE) is a set of space exposure experiments using the International Space Station (ISS) as the flight platform. MISSE 5 is a co-operative endeavor by NASA-LaRC, United Stated Naval Academy, Naval Center for Space Technology (NCST), NASA-GRC, NASA-MSFC, Boeing, AZ Technology, MURE, and Team Cooperative. The primary experiment is performance measurement and monitoring of high performance solar cells for U.S. Navy research and development. A secondary experiment is the telemetry of this data to ground stations. A third experiment is the measurement of low-Earth-orbit (LEO) low-Sun-exposure space effects on thin film materials. Thin films can provide extremely efficacious thermal control, designation, and propulsion functions in space to name a few applications. Solar ultraviolet radiation and atomic oxygen are major degradation mechanisms in LEO. This paper is an engineering report of the MISSE 5 thm films 13 months space exposure experiment.

  11. Driving towards superconducting thin films of Sr2RuO4: A status report

    NASA Astrophysics Data System (ADS)

    Cai, Xinxin; Misra, Rajiv; Myers, Ronald; Ying, Yiqun; Schiffer, Peter; Liu, Ying; Adamo, Carolina; Shen, Kyle; Schlom, Darrell

    2010-03-01

    Chiral p-wave superconductor Sr2RuO4 has attracted attention recently in the context of quantum computing because of the proposed possibility of using this exotic superconductor to make topologically protected qubits. To accomplish this, however, superconducting thin films of Sr2RuO4 are required. Our latest drive towards this long-standing goal has involved the growth of epitaxial thin films of Sr2RuO4 using molecular beam epitaxy (MBE) and the characterization by various techniques. We carried out electrical and magneto transport and scanning Raman spectroscopy measurements on c-axis oriented Sr2RuO4 films grown on (100) LSAT substrates, and demonstrated steady progress on improving the film quality. However, the lowest residual resistivity obtained so far suggests that the films are still not of sufficiently high quality to exhibit superconductivity, which will be confirmed by measurements down to dilution refrigerator temperatures. Nevertheless, interesting behavior, such as an unexpected linear temperature dependence in resistivity, has been found. Additional measurements, such as tunneling, are being pursued to clarify the origin of this observation. The work is supported by DOE, DOD ARO and NSF.

  12. Substrate surface engineering for tailoring properties of functional ceramic thin films

    NASA Astrophysics Data System (ADS)

    Habermeier, H.-U.

    2004-05-01

    Using oxide substrates for functional ceramic thin film deposition beyond their usual application as chemical inert, lattice-matched support for the films represents a novel concept in ceramic thin film research. The substrates are applied as a functional element in order to controllably modify the atom arrangement and the growth mode of ceramic prototype materials such as cuprate superconductors and colossal magnetoresistance manganites. One example is the use of epitaxial strain to adjust the relative positions of cations and anions in the film and thus modify their physical properties. The other makes use of vicinal cut SrTiO3 which enables the fabrication of regular nanoscale step and terrace structures. In YBa2Cu3O7-x thin films grown on vicinal cut SrTiO3 single crystals a regular array of antiphase boundaries is generated causing an anisotropic enhancement of flux-line pinning. In the case of La-Ca-Mn-O thin films grown on vicinal cut substrates it could be demonstrated that magnetic in-plane anisotropy is achieved.

  13. Transverse freezing of thin liquid films

    NASA Astrophysics Data System (ADS)

    Beerman, Michael

    A pair of coupled non-linear partial differential equations is derived using lubrication theory that govern the morphology of a thin, liquid film of a pure and a binary metal alloy, bounded by the liquid's solid phase and a passive gas phase. The analysis is motivated by the directional freezing of metallic foams, and is a first attempt to model transverse freezing in thin films that form in foam networks, but also applies to thin film layers in general. Both the no-slip crystal-melt and the free melt-gas interfaces are deformable. The governing pair of non-linear differential equations for the most general case incorporate crystal-melt and melt-gas surface tension, latent heat, heat transfer, volume change, molecular interactions, thermocapillary and dilute phase concentration effects. Linear analysis of a uniform film reveals a variety of instabilities. A unique wavenumber is selected at the onset of instability in the case of an applied temperature gradient with vanishing crystal-melt surface tension. This system reproduces the isothermal result for a rigid solid-liquid interface in which a band of wavenumbers is unstable. A new long-wave instability has been identified, for the case with CM surface tension, that is due to the coupling of the interfaces. Numerical solutions of the fully non-linear system provide film evolution and rupture times, and show that, near the critical conditions, rupture can occur by the growth of standing or traveling waves. The numerics also reveals complex non-linear interactions between unstable modes. It is found that for most unstable initial conditions, the crystal-melt interface retreats by melting away from the tip region of the encroaching melt-gas interface due to a rise in heat flux as the film thins near the rupture point.

  14. Magnon dispersion in thin magnetic films.

    PubMed

    Balashov, T; Buczek, P; Sandratskii, L; Ernst, A; Wulfhekel, W

    2014-10-01

    Although the dispersion of magnons has been measured in many bulk materials, few studies deal with the changes in the dispersion when the material is in the form of a thin film, a system that is of interest for applications. Here we review inelastic tunneling spectroscopy studies of magnon dispersion in Mn/Cu3Au(1?0?0) and present new studies on Co and Ni thin films on Cu(1?0?0). The dispersion in Mn and Co films closely follows the dispersion of bulk samples with negligible dependence on thickness. The lifetime of magnons depends slightly on film thickness, and decreases considerably as the magnon energy increases. In Ni/Cu(1?0?0) films the thickness dependence of dispersion is much more pronounced. The measurements indicate a considerable mode softening for thinner films. Magnon lifetimes decrease dramatically near the edge of the Brillouin zone due to a close proximity of the Stoner continuum. The experimental study is supported by first-principles calculations. PMID:25212555

  15. Magnetic Structure of Engineered Multiferroic Thin Films

    NASA Astrophysics Data System (ADS)

    Ke, Xianglin

    2011-03-01

    The intriguing properties of multiferroics, i.e., materials exhibiting the coexistence of magnetism and ferroelectricity, have stimulated intense research interest in recent years. From the viewpoint of practical applications, one needs to exploit the thin film architectures of multiferroic materials. However, fewer studies have addressed the magnetic structures of multiferroic thin films. I will present recent experimental works on two multiferroic films, BiFeO3 and EuTiO3, physical properties of which can be engineered via the epitaxial growth on appropriate substrates. Neutron diffraction studies on BiFeO3 films deposited on vicinal SrTiO3 substrates show that the magnetic structure of these films is closely correlated with the ferroelectric states that depend on the chosen substrate miscut [1]. Epitaxial EuTiO3 grown on DyScO3 susbtrate, which is a paraelectric antiferromagnet in its bulk form, is strain-tuned into multiferroics, displaying both ferroelectric and ferromagnetic characters [2]. The relationship between the strong magnetic anisotropy and the film microstructure will be discussed. [4pt] [1] X. Ke, P. P. Zhang, S. Baek, J. Zarestky, W. Tian, and C. B. Eom, Phys. Rev. B 82, 134448 (2010). [0pt] [2] J. H. Lee, L. Fang, E. Vlahos, X. Ke, Y.W. Jung et al., Nature 466, 954 (2010).

  16. Diamond Magnetometry of Superconducting Thin Films

    E-print Network

    A. Waxman; H. Schlussel; D. Groswasser; V. M. Acosta; L. -S. Bouchard; D. Budker; R. Folman

    2014-02-05

    In recent years diamond magnetometers based on the nitrogen-vacancy (NV) center have been of considerable interest for magnetometry applications at the nanoscale. An interesting application which is well suited for NV centers is the study of nanoscale magnetic phenomena in superconducting materials. We employ the magnetic sensitivity of NV centers in diamond to interrogate the magnetic properties of a thin-layer yttrium barium copper oxide (YBCO) superconductor. Using fluorescence-microscopy methods and samples integrated with an NV sensor on a microchip, we measure the temperature of phase transition in the layer to be 70.0(2) K, and the penetration field of vortices to be 46(4) G. We observe the pinning of the vortices in the layer at 65 K, and estimate their density after cooling the sample in a ~ 10 G field to be 0.45(1) \\mu m^{-2}. These measurements are done with a 10 nm thick NV layer, so that high spatial resolution may be enabled in the future. Based on these results, we anticipate that this magnetometer could be useful for imaging the structure and dynamics of vortices. As an outlook, we present a fabrication method for a superconductor chip designed for this purpose.

  17. Structural characterization and magnetoresistance of manganates thin films and Fe-doped manganates thin films

    Microsoft Academic Search

    S. Canulescu; Th. Lippert; H. Grimmer; A. Wokaun; R. Robert; D. Logvinovich; A. Weidenkaff; M. Doebeli

    2006-01-01

    Perovskites thin films with the composition La0.6Ca0.4MnO3 doped with 20% Fe, were prepared by pulsed reactive crossed beam laser ablation, where a synchronized reaction gas pulse interacts with the ablation plume. The films were grown on various substrates and the highest colossal magnetoresistance ratio (CMR) was detected by Hall measurements for films grown on LaAlO3 (100), which was selected as

  18. A Multilayered Thin Film Insulator for Harsh Environments

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Blaha, Charles A.; Busfield, A. Rachel; Thomas, Valarie D.

    2002-01-01

    The status of work to develop a reliable high temperature dielectric thin film for use with thin film sensors is presented. The use of thin films to electrically insulate thin film sensors on engine components minimizes the intrusiveness of the sensor and allows a more accurate measurement of the environment. A variety of insulating films were investigated for preventing electrical shorting caused by insulator failure between the sensor and the component. By alternating layers of sputtered high temperature ceramics, a sequence of insulating layers was devised that prevents pinholes from forming completely through the insulator and maintains high electrical resistivity at high temperatures. The major technical challenge remaining is to optimize the fabrication of the insulator with respect to composition to achieve a reliable high temperature insulating film. Data from the testing of various potentially insulating thin film systems is presented and their application to thin film sensors is also discussed.

  19. Transport behavior across the field-driven superconductor-insulator transition in amorphous indium oxide films

    NASA Astrophysics Data System (ADS)

    Kim, Min-Soo

    Superconductor-insulator transition (SIT) in two-dimensional (2D) thin films is a beautiful realization of a zero temperature quantum phase transition (QPT) and has been explored both theoretically and experimentally over the last two decades. In addition to the several intrinsic ways (such as thickness) of tuning the transition, external magnetic field has been used to tune from one ground state to another in various condensed matter systems. Amorphous indium oxide thin films, with their unique capability of tuning the disorder level in the system easily, have been proven to be an excellent model system to study the transport mechanisms near and across the SIT in 2D. In this thesis, magnetic field-driven SIT in 2D films of amorphous InO x is studied. The goal of this work is to understand the microscopic transport mechanisms responsible for driving the SIT when the magnetic field direction is continually varied from being perpendicular to the sample plane to parallel. Applying a perpendicular magnetic field resulting in a clear field-driven SIT and a magneto-resistance peak on the insulating side in InO x films have been previously understood in a bosonic picture put forward by M. P. A. Fisher and coworkers. However, this boson-vortex duality picture is expected to give rise to markedly different transport characteristics when the magnetic field is applied parallel to the sample plane. Features found in the parallel-field transport data however can also be explained by the bosonic picture, thereby questioning the applicability of the hitherto successful models to the physics of SIT. An isotropic magnetic field value, where the sample has the exact same resistance irrespective of the angle between the sample plane and magnetic field direction, is found. This isotropic point lies at field values above the critical field (Bc) of the SIT (in both perpendicular and parallel configurations) and above the magnetoresistance peak. The isotropic point is very weakly dependent on disorder levels and is temperature-independent. These observations suggest a possible fermionic role in the conduction near the quantum critical point of the SIT and would require newer models to be developed to completely understand the physics. Current-voltage characteristics measured in superconducting samples (below Bc) show that the true superconducting behavior (with a critical current to conduction) appears only in the B = 0 limit. Especially, application of a small magnetic field (˜ 0.2 T) drives the system into a flux flow regime and hence dissipative. The role of this dissipative channel in the superconducting phase in driving the SIT is not well understood. Competing roles of dissipation and bosonic mechanisms need to be treated simultaneously to decipher the underlying physics. When magnetic field is applied to a mesoscopic scale superconducting film, the film breaks into puddles of superconductors and insulators, thereby suggesting percolation-type transport behavior near the quantum critical point. Interestingly, the nonuniform nature of conduction occurs only in magnetic fields below and above Bc at very low temperature below ˜ 400 mK and the sample is completely homogeneous at B c. A complete understanding of the scale of inhomogeneous regions and their role in driving the QPT are still unclear. And the results presented suggest that more experimental and theoretical efforts are needed for understanding the physics near the QPT clearly.

  20. Thermal expansion properties of thin multilayer films

    NASA Astrophysics Data System (ADS)

    Cheng, Xianchao; Morawe, Christian; Peffen, Jean-Christophe; Zhang, Lin

    2014-09-01

    Under synchrotron radiation white beam exposure, strong mechanical stress can build up in multilayer optics, caused by the thermal mismatch between layer material and substrate material. To study the stability and performance of multilayer optics under heat load, Pd, Cr, and B4C single layers of thicknesses in the nanometer range and [Pd/B4C] multilayers were prepared in the sputter-depositing facility of the ESRF Multilayer Laboratory. Curvature changes versus temperature were measured using a Shack-Hartmann wave front sensor. Films coated on 200 ?m thin Si wafers induced significant curvature changes over a temperature range from 60°C to 200°C. A combined parameter K including Young's modulus and thermal expansion coefficient (CTE) was defined to describe the thermal deformation properties of the thin-film layer. The investigation shows that all three materials in thin film cause less thermal expansion than expected from material properties for bulk material in the literature. In particular, the thermal expansion of B4C films appears to be close to that of the Si substrate.

  1. O thin films prepared by electrodeposition

    NASA Astrophysics Data System (ADS)

    Jiang, Xishun; Zhang, Miao; Shi, Shiwei; He, Gang; Song, Xueping; Sun, Zhaoqi

    2014-05-01

    Cuprous oxide (Cu2O) thin films were prepared by using electrodeposition technique at different applied potentials (-0.1, -0.3, -0.5, -0.7, and -0.9 V) and were annealed in vacuum at a temperature of 100°C for 1 h. Microstructure and optical properties of these films have been investigated by X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), UV-visible (vis) spectrophotometer, and fluorescence spectrophotometer. The morphology of these films varies obviously at different applied potentials. Analyses from these characterizations have confirmed that these films are composed of regular, well-faceted, polyhedral crystallites. UV-vis absorption spectra measurements have shown apparent shift in optical band gap from 1.69 to 2.03 eV as the applied potential becomes more cathodic. The emission of FL spectra at 603 nm may be assigned as the near band-edge emission.

  2. Structural characterization of zinc stannate thin films

    NASA Astrophysics Data System (ADS)

    Young, D. L.; Williamson, D. L.; Coutts, T. J.

    2002-02-01

    Polycrystalline thin films of Zn2SnO4 were deposited by rf magnetron sputtering onto glass substrates. Films were characterized by ?-2? x-ray diffraction and by 119Sn conversion electron Mössbauer spectroscopy. The films were randomly oriented in a cubic spinel structure. Comparison of x-ray diffraction peak intensities with structure-factor-calculated peak intensities confirmed that the films were in an inverse spinel configuration. Mössbauer studies detected two distinct Sn4+ octahedral sites. These distinct sites may be induced by distortions in the lattice associated with equally distinct Zn2+ octahedral sites. A model is suggested to explain that the relatively low electron mobility of Zn2SnO4 may be associated with disorder on the cation octahedral sites. This may disrupt transport between edge-sharing d10s0 electronically configured cations.

  3. Thin uranium dioxide films with embedded xenon

    NASA Astrophysics Data System (ADS)

    Usov, I. O.; Dickerson, R. M.; Dickerson, P. O.; Hawley, M. E.; Byler, D. D.; McClellan, K. J.

    2013-06-01

    The ion beam assisted deposition (IBAD) method was applied as a means to incorporate Xe atoms into UO2 films to fabricate reference samples that are representative of an irradiated nuclear fuel without an actual reactor irradiation. The characterization of Xe content and the films microstructure was performed using Rutherford backscattering spectroscopy (RBS), atomic force microscopy (AFM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDXS). A set of UO2 films with excellent control of Xe content ranging from ˜1.0 to 4.0 at.% was fabricated. The thin UO2 films deposited on single crystalline 4H-SiC substrates were found to be composed primarily of randomly oriented nanocrystalline grains and a small fraction of amorphous material. TEM analysis detected no Xe-filled bubbles at a scale of 2.5 nm or larger.

  4. Adhesion assessment of copper thin films

    SciTech Connect

    Kriese, M.D.; Gerberich, W.W. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering; Moody, N.R. [Sandia National Labs., Livermore, CA (United States)

    1997-06-01

    Nano-indentation testing has been used to quantitatively assess the adhesion of thin copper films, sputtered to thicknesses of 150 nm to 1500 nm. Copper films of low residual stress were deposited via RF diode cathode sputtering onto SiO{sub 2}/Si substrates. Overlayers of DC magnetron sputtered tungsten, 850 nm thick with high residual stress, were additionally used to provide a driving force for delamination. All films tested exhibited buckle-driven delamination, from which the interfacial toughness was estimated to be 0.2 - 2 J/m{sup 2}, which is comparable to the thermodynamic work of adhesion. The use of an overlayer requires extensions of existing models, but otherwise does not change the interfacial adhesion, allowing measurements of films that would not otherwise delaminate.

  5. Borides in thin film technology

    SciTech Connect

    Mitterer, C. [Institut fuer Metallkunde und Werkstoffpruefung, Leoben (Austria)] [Institut fuer Metallkunde und Werkstoffpruefung, Leoben (Austria)

    1997-10-01

    The borides of transition and rare-earth metals are considered for application as wear- and corrosion-resistant, decorative or thermionic coatings. After a review of physical vapor deposition (PVD) techniques used for the deposition of these coatings, a survey of investigations to apply these coatings is given. As a result of the strong directionality of covalent boron-boron bonds, boride coatings show an increasing tendency to amorphous film growth with increasing B/Me atomic ratio and, for rare-earth hexaborides, with decreasing metallic radius of the rare-earth metal. Mechanical and optical properties are strongly influenced by the crystallographic structure of the boride phase. Because of their high hardness combined with good adhesion, crystalline films based on the diborides of transition metals seem to be promising candidates for wear resistant coatings on cutting tools. Alloying of these films with nitrogen by reactive PVD processes results in the formation of extremely fine-grained multiphase hard coatings with excellent tribological and corrosion behavior, thus offering new applications in the coating of engineering components. Because of their distinct colorations, some of the hexaborides of rare-earth elements may be used as decorative coatings on consumer products like wristwatch casings or eyeglass frames. Another promising field is the development of thermionic coatings based on rare-earth hexaborides, which may offer the possibility of the production of inexpensive and simple high emission filaments.

  6. Extending the 3? method: Thermal conductivity characterization of thin films

    NASA Astrophysics Data System (ADS)

    Bodenschatz, Nico; Liemert, André; Schnurr, Sebastian; Wiedwald, Ulf; Ziemann, Paul

    2013-08-01

    A lock-in technique for measurement of thermal conductivity and volumetric heat capacity of thin films is presented. The technique is based on the 3? approach using electrical generation and detection of oscillatory heat along a thin metal strip. Thin films are deposited onto the backside of commercial silicon nitride membranes, forming a bilayer geometry with distinct thermal parameters. Stepwise comparison to an adapted heat diffusion model delivers these parameters for both layers. Highest sensitivity is found for metallic thin films.

  7. Investigation of TiOx barriers for their use in hybrid Josephson and tunneling junctions based on pnictide thin films

    NASA Astrophysics Data System (ADS)

    Döring, S.; Monecke, M.; Schmidt, S.; Schmidl, F.; Tympel, V.; Engelmann, J.; Kurth, F.; Iida, K.; Haindl, S.; Mönch, I.; Holzapfel, B.; Seidel, P.

    2014-02-01

    We tested oxidized titanium layers as barriers for hybrid Josephson junctions with high IcRn-products and for the preparation of junctions for tunneling spectroscopy. For that we firstly prepared junctions with conventional superconductor electrodes, such as lead and niobium, respectively. By tuning the barrier thickness, we were able to change the junction's behavior from a Josephson junction to tunnel-like behavior applicable for quasi-particle spectroscopy. Subsequently, we transferred the technology to junctions using Co-doped BaFe2As2 thin films prepared by pulsed laser deposition as base electrode and evaporated Pb as counter electrode. For barriers with a thickness of 1.5 nm, we observe clear Josephson effects with IcRn?90 ?V at 4.2 K. These junctions behave SNS'-like (SNS: superconductor-normal conductor-superconductor) and are dominated by Andreev reflection transport mechanism. For junctions with barrier thickness of 2.0 nm and higher, no Josephson but SIS'- (SIS: superconductor-insulator-superconductor) or SINS'-like (SINS: superconductor-normal conductor-insulator-superconductor) behavior with a tunnel-like conductance spectrum was observed.

  8. Elastic Properties of Molecular Glass Thin Films

    NASA Astrophysics Data System (ADS)

    Torres, Jessica

    2011-12-01

    This dissertation provides a fundamental understanding of the impact of bulk polymer properties on the nanometer length scale modulus. The elastic modulus of amorphous organic thin films is examined using a surface wrinkling technique. Potential correlations between thin film behavior and intrinsic properties such as flexibility and chain length are explored. Thermal properties, glass transition temperature (Tg) and the coefficient of thermal expansion, are examined along with the moduli of these thin films. It is found that the nanometer length scale behavior of flexible polymers correlates to its bulk Tg and not the polymers intrinsic size. It is also found that decreases in the modulus of ultrathin flexible films is not correlated with the observed Tg decrease in films of the same thickness. Techniques to circumvent reductions from bulk modulus were also demonstrated. However, as chain flexibility is reduced the modulus becomes thickness independent down to 10 nm. Similarly for this series minor reductions in T g were obtained. To further understand the impact of the intrinsic size and processing conditions; this wrinkling instability was also utilized to determine the modulus of small organic electronic materials at various deposition conditions. Lastly, this wrinkling instability is exploited for development of poly furfuryl alcohol wrinkles. A two-step wrinkling process is developed via an acid catalyzed polymerization of a drop cast solution of furfuryl alcohol and photo acid generator. The ability to control the surface topology and tune the wrinkle wavelength with processing parameters such as substrate temperature and photo acid generator concentration is also demonstrated. Well-ordered linear, circular, and curvilinear patterns are also obtained by selective ultraviolet exposure and polymerization of the furfuryl alcohol film. As a carbon precursor a thorough understanding of this wrinkling instability can have applications in a wide variety of technologies.

  9. Thermal conductivities of thin, sputtered optical films

    NASA Astrophysics Data System (ADS)

    Henager, C. H., Jr.; Pawlewicz, W. T.

    1991-05-01

    The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO2/Si3N4)(n) and Al(Al2O3/AIN)(n). Sputtered films of more conventional materials like SiO2, Al2O3, Ta2O5, Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented.

  10. Electrohydrodynamic instabilities in thin liquid trilayer films

    DOE PAGESBeta

    Roberts, Scott A. [Sandia National Lab., Albuquerque, NM (United States); Kumar, Satish [Univ. of Minnesota, Minneapolis, MN (United States)

    2010-09-12

    Experiments by Dickey et al. [Langmuir, 22, 4315 (2006)] and Leach et al. [Chaos, 15, 047506 (2005)] show that novel pillar shapes can be generated from electrohydrodynamic instabilities at the interfaces of thin polymer/polymer/air trilayer films. In this paper, we use linear stability analysis to investigate the effect of free charge and ac electric fields on the stability of trilayer systems. Our work is also motivated by our recent theoretical study [J. Fluid Mech., 631, 255 (2009)] which demonstrates how ac electric fields can be used to increase control over the pillar formation process in thin liquid bilayer films. For perfect dielectric films, the effect of an AC electric field can be understood by considering an equivalent DC field. Leaky dielectric films yield pillar configurations that are drastically different from perfect dielectric films, and AC fields can be used to control the location of free charge within the trilayer system. This can alter the pillar instability modes and generate smaller diameter pillars when conductivities are mismatched. The results presented here may be of interest for the creation of complex topographical patterns on polymer coatings and in microelectronics.

  11. Piezoresistance in chemically synthesized polypyrrole thin films

    E-print Network

    S. Barnoss; H. Shanak; C. Bof Bufon; T. Heinzel

    2009-08-26

    The resistance of chemically synthesized polypyrrole (PPy) thin films is investigated as a function of the pressure of various gases as well as of the film thickness. A physical, piezoresistive response is found to coexist with a chemical response if the gas is chemically active, like, e.g., oxygen. The piezoresistance is studied separately by exposing the films to the chemically inert gases such as nitrogen and argon. We observe that the character of the piezoresistive response is a function not only of the film thickness, but also of the pressure. Films of a thickness below 70 nm show a decreasing resistance as pressure is applied, while for thicker films, the piezoresistance is positive. Moreover, in some films of thickness of about 70 nm, the piezoresistive response changes from negative to positive as the gas pressure is increased above 500 mbars. This behavior is interpreted in terms of a total piezoresistance which is composed of a surface and a bulk component, each of which contributes in a characteristic way. These results suggest that in polypyrrole, chemical sensing and piezoresistivity can coexist, which needs to be kept in mind when interpreting resistive responses of such sensors.

  12. Nitrogen doped zinc oxide thin film

    SciTech Connect

    Li, Sonny X.

    2003-12-15

    To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO{sub 2} plasma or by N{sup +} implantation. All ZnO films grown show n-type conductivity. In unintentionally doped ZnO films, the n-type conductivities are attributed to Zn{sub i}, a native shallow donor. In NO{sub 2}-grown ZnO films, the n-type conductivity is attributed to (N{sub 2}){sub O}, a shallow double donor. In NO{sub 2}-grown ZnO films, 0.3 atomic % nitrogen was found to exist in the form of N{sub 2}O and N{sub 2}. Upon annealing, N{sub 2}O decomposes into N{sub 2} and O{sub 2}. In furnace-annealed samples N{sub 2} redistributes diffusively and forms gaseous N{sub 2} bubbles in the films. Unintentionally doped ZnO films were grown at different oxygen partial pressures. Zni was found to form even at oxygen-rich condition and led to n-type conductivity. N{sup +} implantation into unintentionally doped ZnO film deteriorates the crystallinity and optical properties and leads to higher electron concentration. The free electrons in the implanted films are attributed to the defects introduced by implantation and formation of (N{sub 2}){sub O} and Zni. Although today there is still no reliable means to produce good quality, stable p-type ZnO material, ZnO remains an attractive material with potential for high performance short wavelength optoelectronic devices. One may argue that gallium nitride was in a similar situation a decade ago. Although we did not obtain any p-type conductivity, we hope our research will provide a valuable reference to the literature.

  13. Effect of annealing on the superconducting properties of a-NbxSi1-x thin films

    NASA Astrophysics Data System (ADS)

    Crauste, O.; Gentils, A.; Couëdo, F.; Dolgorouky, Y.; Bergé, L.; Collin, S.; Marrache-Kikuchi, C. A.; Dumoulin, L.

    2013-04-01

    a-NbxSi1-x thin films with thicknesses down to 25 Å have been structurally characterized by transmission electron microscopy measurements. As-deposited or annealed films are shown to be continuous and homogeneous in composition and thickness, up to an annealing temperature of 500 ?C. We have carried out low-temperature transport measurements on these films close to the superconductor-to-insulator transition (SIT) and shown a qualitative difference between the effect of annealing or composition and a reduction of the film thickness on the superconducting properties of a-NbSi. These results question the pertinence of the sheet resistance R? as the relevant parameter to describe the SIT.

  14. Modification and nano-patterning of high-Tc superconducting thin films by masked ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Bodea, M. A.; Pedarnig, J. D.; Siraj, K.; Behbood, N.; Bäuerle, D.; Lang, W.; Hasenfuss, C.; Palmetshofer, L.; Haselgrübler, K.; Kolarova, R.; Bauer, P.

    2010-06-01

    Ion irradiation of the high-temperature superconductor (HTS) YBa2Cu3O7 (Y-123) creates different types of defects depending on ion mass, energy and dose. Irradiation with helium ions of moderate energy (75 keV) primarily creates point defects. We measure in situ the modification of electrical transport properties of Y-123 thin films (thickness 310 nm) during ion irradiation. The He ions penetrate thin films and produce collision cascades with small lateral straggle that allow for patterning of nanostructures in the HTS layer. We present features smaller than 100 nm in size produced by masked ion beam irradiation of Y-123 films. Computer simulations indicate that nano-patterning of Y-123 thin films with 10 nm lateral resolution is achievable.

  15. Substrate heater for thin film deposition

    DOEpatents

    Foltyn, Steve R. (111 Beryl St., Los Alamos, NM 87544)

    1996-01-01

    A substrate heater for thin film deposition of metallic oxides upon a target substrate configured as a disk including means for supporting in a predetermined location a target substrate configured as a disk, means for rotating the target substrate within the support means, means for heating the target substrate within the support means, the heating means about the support means and including a pair of heating elements with one heater element situated on each side of the predetermined location for the target substrate, with one heater element defining an opening through which desired coating material can enter for thin film deposition and with the heating means including an opening slot through which the target substrate can be entered into the support means, and, optionally a means for thermal shielding of the heating means from surrounding environment is disclosed.

  16. Domain switching of fatigued ferroelectric thin films

    SciTech Connect

    Tak Lim, Yun [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Yeog Son, Jong, E-mail: jyson@khu.ac.kr, E-mail: hoponpop@ulsan.ac.kr [Department of Applied Physics, College of Applied Science, Kyung Hee University, Suwon 446-701 (Korea, Republic of); Shin, Young-Han, E-mail: jyson@khu.ac.kr, E-mail: hoponpop@ulsan.ac.kr [Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

    2014-05-12

    We investigate the domain wall speed of a ferroelectric PbZr{sub 0.48}Ti{sub 0.52}O{sub 3} (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue.

  17. Electrostatic Discharge Effects on Thin Film Resistors

    NASA Technical Reports Server (NTRS)

    Sampson, Michael J.; Hull, Scott M.

    1999-01-01

    Recently, open circuit failures of individual elements in thin film resistor networks have been attributed to electrostatic discharge (ESD) effects. This paper will discuss the investigation that came to this conclusion and subsequent experimentation intended to characterize design factors that affect the sensitivity of resistor elements to ESD. The ESD testing was performed using the standard human body model simulation. Some of the design elements to be evaluated were: trace width, trace length (and thus width to length ratio), specific resistivity of the trace (ohms per square) and resistance value. However, once the experiments were in progress, it was realized that the ESD sensitivity of most of the complex patterns under evaluation was determined by other design and process factors such as trace shape and termination pad spacing. This paper includes pictorial examples of representative ESD failure sites, and provides some options for designing thin film resistors that are ESD resistant. The risks of ESD damage are assessed and handling precautions suggested.

  18. Thin film strain gage development program

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Przybyszewski, J. S.; Anderson, W. L.; Claing, R. G.

    1983-01-01

    Sputtered thin-film dynamic strain gages of 2 millimeter (0.08 in) gage length and 10 micrometer (0.0004 in) thickness were fabricated on turbojet engine blades and tested in a simulated compressor environment. Four designs were developed, two for service to 600 K (600 F) and two for service to 900 K (1200 F). The program included a detailed study of guidelines for formulating strain-gage alloys to achieve superior dynamic and static gage performance. The tests included gage factor, fatigue, temperature cycling, spin to 100,000 G, and erosion. Since the installations are 30 times thinner than conventional wire strain gage installations, and any alteration of the aerodynamic, thermal, or structural performance of the blade is correspondingly reduced, dynamic strain measurement accuracy higher than that attained with conventional gages is expected. The low profile and good adherence of the thin film elements is expected to result in improved durability over conventional gage elements in engine tests.

  19. Polycrystalline thin films FY 1992 project report

    SciTech Connect

    Zweibel, K. [ed.

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting ``next-generation`` options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called ``government/industry partnerships``) that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  20. Polycrystalline thin films FY 1992 project report

    SciTech Connect

    Zweibel, K. (ed.)

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting next-generation'' options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called government/industry partnerships'') that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  1. Thin film photovoltaic panel and method

    DOEpatents

    Ackerman, Bruce (El Paso, TX); Albright, Scot P. (El Paso, TX); Jordan, John F. (El Paso, TX)

    1991-06-11

    A thin film photovoltaic panel includes a backcap for protecting the active components of the photovoltaic cells from adverse environmental elements. A spacing between the backcap and a top electrode layer is preferably filled with a desiccant to further reduce water vapor contamination of the environment surrounding the photovoltaic cells. The contamination of the spacing between the backcap and the cells may be further reduced by passing a selected gas through the spacing subsequent to sealing the backcap to the base of the photovoltaic panels, and once purged this spacing may be filled with an inert gas. The techniques of the present invention are preferably applied to thin film photovoltaic panels each formed from a plurality of photovoltaic cells arranged on a vitreous substrate. The stability of photovoltaic conversion efficiency remains relatively high during the life of the photovoltaic panel, and the cost of manufacturing highly efficient panels with such improved stability is significantly reduced.

  2. Quasicrystalline thin films: Growth, structure and interface

    NASA Astrophysics Data System (ADS)

    Widjaja, Edy

    Quasicrystals are orientation-ordered structures with classically forbidden rotation symmetries (e.g. 5-fold and 10-fold rotation axes) which are incompatible with periodic translational ordering. Quasicrystalline materials exhibit properties that are very different from conventional metallic materials. Two systems of quasicrystalline alloys have been studied in this thesis work: decagonal Al-Cu-Fe-Cr and icosahedral Al-Cu-Fe. Thin films were grown by magnetron sputtering system on various substrates and studied by Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy. The growth mode at room and elevated temperatures has been investigated in-situ and ex-situ. An microstructural evolution study during the phase transformation to the quasicrystalline state has also been performed. Epitaxial quasicrystalline thin films have been successfully grown on crystalline substrates. A coincidence reciprocal lattice planes model was developed to describe the interface of quasicrystals and crystals.

  3. Thin-film optical shutter. Final report

    SciTech Connect

    Matlow, S.L.

    1981-02-01

    A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

  4. Structures for dense, crack free thin films

    DOEpatents

    Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); De Jonghe, Lutgard C. (Lafayette, CA)

    2011-03-08

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  5. Packaging material for thin film lithium batteries

    DOEpatents

    Bates, John B. (116 Baltimore Dr., Oak Ridge, TN 37830); Dudney, Nancy J. (11634 S. Monticello Rd., Knoxville, TN 37922); Weatherspoon, Kim A. (223 Wadsworth Pl., Oak Ridge, TN 37830)

    1996-01-01

    A thin film battery including components which are capable of reacting upon exposure to air and water vapor incorporates a packaging system which provides a barrier against the penetration of air and water vapor. The packaging system includes a protective sheath overlying and coating the battery components and can be comprised of an overlayer including metal, ceramic, a ceramic-metal combination, a parylene-metal combination, a parylene-ceramic combination or a parylene-metal-ceramic combination.

  6. Investigation of mechanical properties of transparent conducting oxide thin films

    Microsoft Academic Search

    Kaiyang Zeng; Furong Zhu; Jianqiao Hu; Lu Shen; Keran Zhang; Hao Gong

    2003-01-01

    We present an analysis of the mechanical properties of transparent conducting oxide (TCO), indium tin oxide (ITO) and indium zinc oxide (IZO) thin films on the glass substrates. The thin films of ITO and IZO were deposited by radio frequency magnetron sputtering at a low processing temperature. The elastic modulus and hardness of the TCO films prepared at different deposition

  7. Thickness-dependent properties of sprayed iridium oxide thin films

    Microsoft Academic Search

    P. S Patil; P. S Chigare; S. B Sadale; T Seth; D. P Amalnerkar; R. K Kawar

    2003-01-01

    Iridium oxide thin films with variable thickness were deposited by spray pyrolysis technique (SPT), onto the amorphous glass substrates kept at 350°C. The volume of iridium chloride solution was varied to obtain iridium oxide thin films with thickness ranging from 700 to 2250Å. The effect of film thickness on structural and electrical properties was studied. The X-ray diffraction (XRD) studies

  8. Preparation of thin polymer films for infrared reaction rate studies

    NASA Technical Reports Server (NTRS)

    Garrard, G. G.; Houston, D. W.

    1970-01-01

    Procedure for preparing thin films for infrared spectrophotometric analysis involves pressing of a neat mixture of reactants between nonreactive thin polymer films with noninterfering absorption bands. Pressing is done under a pressure that gives desirable thickness. Following this process, the film sandwich is cut to accommodate the laboratory instrument.

  9. Magnetic and structural characteristics of sputtered barium ferrite thin films

    Microsoft Academic Search

    Jinshan Li; Stephen S. Rosenbluem; Hidetaka Hayashi; Robert Sinclair

    1996-01-01

    ? M curves have been measured on both randomly and perpendicularly oriented barium ferrite thin films. Compared with theoretical simulations, the shape and peak values of the ? M curves suggest that the intergranular exchange interaction in sputtered BaM thin films is negligible. This is similar to the case of oxide particulate media even though the sputtered films are much

  10. Ultraviolet Surface Plasmon-Coupled Emission Using Thin Aluminum Films

    Microsoft Academic Search

    Ignacy Gryczynski; Joanna Malicka; Zygmunt Gryczynski; Kazimierz Nowaczyk; Joseph R. Lakowicz

    2004-01-01

    Surface plasmon-coupled emission (SPCE) is the direc- tional radiation of light into a substrate due to excited fluorophores above a thin metal film. To date, SPCE has only been observed with visible wavelengths using silver or gold films. We now show that SPCE can be observed in the ultraviolet region of the spectrum using thin (20 nm) aluminum films. We

  11. Fracture patterns in thin films and multilayers Alex A. Volinsky

    E-print Network

    Volinsky, Alex A.

    Fracture patterns in thin films and multilayers Alex A. Volinsky University of South Florida, excessive residual and externally applied stresses cause film fracture. In the case of tensile stress is the key for causing thin film fracture, either in tension, or compression, it is the influence

  12. Polymer-Metal Nanocomposites via Polymer Thin Film

    E-print Network

    Shyamasundar, R.K.

    Polymer-Metal Nanocomposites via Polymer Thin Film T. P. Radhakrishnan School of Chemistry, University of Hyderabad Polymer-metal nanocomposite thin films are versatile materials that not only characteristics of the components, but also manifest mutualistic effects. Soft c film is a facile in situ of metal

  13. Stabilization mechanism of electrodeposited silicon thin films.

    PubMed

    Vichery, C; Le Nader, V; Frantz, C; Zhang, Y; Michler, J; Philippe, L

    2014-10-28

    Amorphous composite silicon thin films electrodeposited in tetrahydrofuran, containing up to 80 at% of Si and exhibiting an homogeneous dispersions of O, C and Cl in the amorphous Si matrix, have been successfully stabilized against oxidation using a post-annealing step in inert atmosphere. In order to understand the impact of the annealing step on their stabilization against oxidation, their composition and structure have been investigated upon heat treatments. It has been shown that the presence of impurities such as O, C and Cl does not have any impact on the stabilization process, which is rather linked to the presence of hydrogen in the Si composites. This conclusion has been drawn after a detailed analysis of the bonding structure of films annealed at different temperatures and dwell times by the mean of Raman spectroscopy. It has been shown that annealing the as-deposited films at 350 °C for a couple of hours or at higher temperatures induced a hydrogen evolution, characterized by the breaking of Si-H bonds and the formation of Si-Si bonds, which stabilized the silicon network. The understanding and the reproducibility of this stabilization process of silicon thin film electrodeposited in organic solvent paves the way for their use for many applications. PMID:25212513

  14. Thin film cadmium telluride photovoltaic cells

    SciTech Connect

    Compaan, A.; Bohn, R. (Toledo Univ., OH (United States))

    1992-04-01

    This report describes research to develop to vacuum-based growth techniques for CdTe thin-film solar cells: (1) laser-driven physical vapor deposition (LDPVD) and (2) radio-frequency (rf) sputtering. The LDPVD process was successfully used to deposit thin films of CdS, CdTe, and CdCl{sub 2}, as well as related alloys and doped semiconductor materials. The laser-driven deposition process readily permits the use of several target materials in the same vacuum chamber and, thus, complete solar cell structures were fabricated on SnO{sub 2}-coated glass using LDPVD. The rf sputtering process for film growth became operational, and progress was made in implementing it. Time was also devoted to enhancing or implementing a variety of film characterization systems and device testing facilities. A new system for transient spectroscopy on the ablation plume provided important new information on the physical mechanisms of LDPVD. The measurements show that, e.g., Cd is predominantly in the neutral atomic state in the plume but with a fraction that is highly excited internally ({ge} 6 eV), and that the typical neutral Cd translational kinetic energies perpendicular to the target are 20 eV and greater. 19 refs.

  15. Leakage currents in thin ferroelectric films

    NASA Astrophysics Data System (ADS)

    Podgornyi, Yu. V.; Vorotilov, K. A.; Sigov, A. S.

    2012-05-01

    The basic mechanisms of leakage current components of thin lead zirconate titanate (PZT) ferroelectric films grown by the sol-gel method have been studied. Characteristic regions of current-voltage characteristics with different charge transport mechanisms have been determined. It has been shown that there is an intermediate region which separates such regions. In one of them, the leakage current depends on properties of the contact of electrodes with PZT film at low voltages; in the other, the leakage current is controlled by intrinsic properties of the PZT film bulk, and the basic mechanism of charge transport is Poole-Frenkel emission. In the intermediate region, a stepwise change in the current has been observed, which is caused by relaxing breakdown of the Schottky barrier. Time dependences of the leakage currents have been determined. It has been shown that the leakage current decreases with increasing delay time before the Schottky barrier breakdown, and the dependence becomes opposite in character after the breakdown.

  16. Metal-doped magnetite thin films.

    PubMed

    Abe, Seishi; Ping, De Hai; Nakamura, Shintaro; Ohnuma, Masato; Ohnuma, Shigehiro

    2012-06-01

    This paper investigates magnetite (Fe3O4) thin film containing a small amount of a metal element. The films are prepared by rf sputtering with a composite target of ceramic iron oxide with metal chips. Low-temperature magnetization of magnetite containing 5.3%Ge reveals that the film contains some magnetically weak coupling grains. The metal element Mg reduces both hematite (alpha-Fe2O3) and magnetite, resulting in single-phase wüstite (Fe1-xO). In contrast, adding Ge selectively reduces hematite, while magnetite remains unreactive. According to the free energy of reaction, the element Ge is able to reduce hematite only, whereas the element Mg is capable of reducing both hematite and magnetite. This property is in good agreement with the experiment results. PMID:22905582

  17. Electron stimulated desorption from thin organic films

    NASA Astrophysics Data System (ADS)

    Dylla, H. F.; Abrams, J. H.; Phillips, B. F.

    1984-09-01

    Electron stimulated desorption (ESD) is examined from a polymerized methylglutamatic acid (PMG) monolayer and from a thin soap film after exposure to a series of adsorbates with varying polarization. ESD spectra from the PMG film are dominated by product ions attributed to the water of hydration (H +, OH +, H 2O +) regardless of subsequent adsorbate exposure. ESD spectra from the soap film also exhibit H 2O related peaks, however, the adsorption of a nonpolar adsorbate (heptane) is detectable through the appearance of H +2 as a desorption product. A linear dependence of ESD product ions with incident electron current is observed. ESD total cross-sections were measured on these surfaces to be in the range of 10 -16-10 -18 cm 2.

  18. Electrohydrodynamic instabilities in thin trilayer liquid films.

    SciTech Connect

    Roberts, Scott A.; Kumar, Satish (University of Minnesota %3CU%2B2013%3E Twin Cities)

    2010-11-01

    When DC or AC electric fields are applied to a thin liquid film, the interface may become unstable and form a series of pillars. We examine how the presence of a second liquid interface influences pillar dynamics and morphologies. For perfect dielectric films, linear stability analysis of a lubrication-approximation-based model shows that the root mean square voltage governs the pillar behavior. For leaky dielectric films, Floquet theory is applied to carry out the linear stability analysis, and reveals that the accumulation of free charge at each interface depends on the conductivities in the adjoining phases and that high frequencies of the AC electric field may be used to control this accumulation at each interface independently. The results presented here may of interest for the controlled creation of surface topographical features in applications such as patterned coatings and microelectronics.

  19. Comparison of the pinning energy in Fe(Se1-xTex) compound between single crystals and thin films

    NASA Astrophysics Data System (ADS)

    Leo, A.; Guarino, A.; Grimaldi, G.; Nigro, A.; Pace, S.; Bellingeri, E.; Kawale, S.; Ferdeghini, C.; Giannini, E.

    2014-05-01

    Among the families of iron-based superconductors, we investigate flux pinning mechanisms in the Fe(Se1-xTex) compound. We perform magneto-resistance and current-voltage measurements on single-crystals, as well as on several epitaxial thin films grown on different substrates (CaF2, LaAlO3). The activation energy is derived as a function of magnetic field, U(H). The influence of magnetic field orientation on the pinning energy activation mechanism is also studied, leading to the anisotropy analysis which reveals low anisotropy in thin films grown on CaF2 substrate with respect to single crystals and films grown on LaAlO3. Concerning the dominant pinning regime, the exponents of the power law dependence U0(H) ~ H-? have been evaluated, confirm that weak pinning is a general characteristic of this compound. The single exponent feature, generally noticed on thin films grown on SrTiO3 substrate and associated to a strong single vortex regime, has been observed in thin films grown on LaAlO3, only in the parallel configuration. At the end, this overall comparison can be useful to develop a technological material able to compete with high temperature superconductors.

  20. Electronic evidence of an insulator-superconductor crossover in single-layer FeSe/SrTiO3 films.

    PubMed

    He, Junfeng; Liu, Xu; Zhang, Wenhao; Zhao, Lin; Liu, Defa; He, Shaolong; Mou, Daixiang; Li, Fangsen; Tang, Chenjia; Li, Zhi; Wang, Lili; Peng, Yingying; Liu, Yan; Chen, Chaoyu; Yu, Li; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Chen, Chuangtian; Xu, Zuyan; Chen, Xi; Ma, Xucun; Xue, Qikun; Zhou, X J

    2014-12-30

    In high-temperature cuprate superconductors, it is now generally agreed that superconductivity is realized by doping an antiferromagnetic Mott (charge transfer) insulator. The doping-induced insulator-to-superconductor transition has been widely observed in cuprates, which provides important information for understanding the superconductivity mechanism. In the iron-based superconductors, however, the parent compound is mostly antiferromagnetic bad metal, raising a debate on whether an appropriate starting point should go with an itinerant picture or a localized picture. No evidence of doping-induced insulator-superconductor transition (or crossover) has been reported in the iron-based compounds so far. Here, we report an electronic evidence of an insulator-superconductor crossover observed in the single-layer FeSe film grown on a SrTiO3 substrate. By taking angle-resolved photoemission measurements on the electronic structure and energy gap, we have identified a clear evolution of an insulator to a superconductor with increasing carrier concentration. In particular, the insulator-superconductor crossover in FeSe/SrTiO3 film exhibits similar behaviors to that observed in the cuprate superconductors. Our results suggest that the observed insulator-superconductor crossover may be associated with the two-dimensionality that enhances electron localization or correlation. The reduced dimensionality and the interfacial effect provide a new pathway in searching for new phenomena and novel superconductors with a high transition temperature. PMID:25502774

  1. Superconducting YBaCuO thin films by Cu-ion implantation

    SciTech Connect

    Hubbard, K.M.; Bordes, N.; Nastasi, M.; Tesmer, J.R.

    1990-01-01

    We have investigated the fabrication of thin-film superconductors by Cu-ion implantation into initially Cu-deficient Y(BaF{sub 2})Cu thin films. The precursor films were co-evaporated on SrTiO{sub 3} substrates, and subsequently implanted to various doses with 400 keV {sup 63}Cu{sup 2+}. Implantations were preformed at both LN{sub 2} temperature, and at 380{degree}C. The films were post-annealed in oxygen, and characterized as a function of dose by four-point probe analysis, x-ray diffraction, ion-beam backscattering and channeling, and scanning electron microscopy. It was found that a significant improvement in film quality could be achieved by heating the films to 380{degree}C during the implantation. The best films became fully superconducting at 60--70 K, and exhibited good metallic R vs. T. behavior in the normal state. 14 refs., 2 figs., 1 tab.

  2. Thin Film Evolution Over a Thin Porous Layer: Modeling a Tear Film on a Contact Lens

    NASA Astrophysics Data System (ADS)

    Anderson, Daniel; Nong, Kumnit

    2010-11-01

    We examine a mathematical model that describes the behavior of the pre-contact lens tear film of a human eye. Our work examines the effect of contact lens thickness and lens permeability and slip on the film dynamics. A mathematical model for the evolution of the tear film is derived using a lubrication approximation applied to the hydrodynamic equations of motion in the fluid film and the porous layer. The model is a nonlinear fourth order partial differential equation subject to boundary conditions and an initial condition for post-blink film evolution. We find that increasing the lens thickness, permeability and slip all contribute to an increase in the film thinning rate although for parameter values typical for contact lens wear these modifications are minor. The presence of the contact lens can, however, fundamentally change the nature of the rupture dynamics as the inclusion of the porous lens leads to rupture in finite time rather than infinite time.

  3. Specific heat measurement set-up for quench condensed thin superconducting films

    NASA Astrophysics Data System (ADS)

    Poran, Shachaf; Molina-Ruiz, Manel; Gérardin, Anne; Frydman, Aviad; Bourgeois, Olivier

    2014-05-01

    We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films.

  4. Specific heat measurement set-up for quench condensed thin superconducting films.

    PubMed

    Poran, Shachaf; Molina-Ruiz, Manel; Gérardin, Anne; Frydman, Aviad; Bourgeois, Olivier

    2014-05-01

    We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films. PMID:24880383

  5. Magnetic relaxation in the 110 K superconducting phase in Bi-Sr-Ca-Cu-O thin films

    NASA Technical Reports Server (NTRS)

    Tanaka, Atsushi; Crain, Jason; Kamehara, Nobuo; Niwa, Koichi

    1991-01-01

    We have investigated the time dependence of remnant moment decay in a highly oriented, nearly single high T(sub c) phase Bi-Sr-Ca-Cu-O thin film. A strictly logarithmic time dependence was observed over a 20 K temperature range for observation intervals of 2000 seconds. The normalized decay rate exhibits a peak around 14 K and has a relatively weak magnetic field dependence. These data are then compared with existing data on the YBCO and Eu-based superconductors.

  6. Functional planar thin film optical waveguide lasers Functional planar thin film optical waveguide lasers

    NASA Astrophysics Data System (ADS)

    Jelínek, M.

    2012-02-01

    Fabrication and characterization of planar and channel waveguiding thin films with the goal to develop active and passive elements are intensively studied over the last 20 years. Large scale of materials and properties were tested (morphology, crystallinity, luminescence, waveguiding, etc.). The goal of our contribution is to give an overview of materials and fabrication processes which were used for development and construction of functional planar waveguide lasers (PWL). The compact survey of finalized PWL and their basic parameters is given. A special part is devoted to fabrication of waveguide lasers using laser technology. Applications of thin film waveguide lasers are mentioned.

  7. Effects of processing parameters on the laser deposition of high temperature superconducting thin films

    SciTech Connect

    Nogar, N.S.; Castain, R.; Dye, R.C.; Foltyn, S.; Muenchausen, R.E.; Wu, X.D.

    1990-01-01

    Y{sub 2}O{sub 3} pressed powders were ablated by pulses from a XeCl excimer laser, operating at 308 nm, 150 mJ/pulse, {approx}15 nsec/pulse and 20 Hz. Emission spectra from Y* and YO* were recorded as a function of ambient oxygen pressure in the range 10{sup {minus}5} -- 4 {times} 10{sup {minus}1} Torr, at a laser fluence of {approx} 4J/cm{sup 2}. A kinetic model is developed to describe the results, and the application to production of laser-deposited high-temperature superconductor thin films is discussed. 13 refs., 4 figs.

  8. Overview and Challenges of Thin Film Solar Electric Technologies

    SciTech Connect

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  9. An improved model of thin film growth

    NASA Astrophysics Data System (ADS)

    Doryland, D. J.

    1985-12-01

    A VAX-11/785 computer was used to simulate the two dimensional growth of thin films produced by vapor deposition. In this model molecules and impurities were represented by three different sized disks. In order to simulate varying deposition conditions and evaporants, several variable parameters were introduced. Among these parameters were the variation of the deposition angle about some main angle, the mobility of the disks upon collision, the ability to introduce impurities into the microstructure, the simulation of multilayered coatings and the ability to introduce imperfections into the substrate. The results obtained by this model show that disks can be used to simulate some of the main features exhibited by vapor deposited films. Among these features are the formation of columns and their compliance with the tangent rule, and the disappearance of this structure in the case of large disk mobility. Another feature found to be exhibited in the modeled films is that under certain conditions impurities and substrate imperfections can produce large voids and/or nodules. Other characteristics found in the simulated films include pores which could allow water absorption, and increased packing density for films produced with angle variations along with a moderate amount of disk mobility.

  10. Growth of c-axis-oriented superconducting KFe?As? thin films.

    PubMed

    Hiramatsu, Hidenori; Matsuda, Shogo; Sato, Hikaru; Kamiya, Toshio; Hosono, Hideo

    2014-08-27

    KFe2As2, an iron-based superconductor, is expected to exhibit large spin Hall conductivity, and fabrication of high-quality thin films is requisite for evaluation of this effect and application to spintronics devices. Thin-film growth of KFe2As2 is difficult because of two intrinsic properties; its extremely hygroscopic nature and the high vapor pressure of potassium. We solved these issues by combining room-temperature pulsed laser deposition using K-rich KFe2As2 targets with thermal crystallization in KFe2As2 powder after encapsulation in an evacuated silica-glass tube with all of the processes conducted in a vacuum chamber and a dry Ar atmosphere in a glovebox. The optimized KFe2As2 films on (La,Sr)(Al,Ta)O3 single-crystal substrates were obtained by crystallization at 700 °C, and they were strongly c-axis oriented. The electrical measurements were performed with thin films protected by grease passivation to block reaction with the atmosphere. The KFe2As2 films exhibited a superconductivity transition at 3.7 K. PMID:25032799

  11. Chemical vapor deposition of organosilicon and sacrificial polymer thin films

    E-print Network

    Casserly, Thomas Bryan

    2005-01-01

    Chemical vapor deposition (CVD) produced films for a wide array of applications from a variety of organosilicon and organic precursors. The structure and properties of thin films were controlled by varying processing ...

  12. Fluorination of amorphous thin-film materials with xenon fluoride

    DOEpatents

    Weil, R.B.

    1987-05-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  13. Fluorination of amorphous thin-film materials with xenon fluoride

    DOEpatents

    Weil, Raoul B. (Haifa, IL)

    1988-01-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  14. Pulsed laser deposition of pepsin thin films

    NASA Astrophysics Data System (ADS)

    Kecskeméti, G.; Kresz, N.; Smausz, T.; Hopp, B.; Nógrádi, A.

    2005-07-01

    Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser ( ? = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm 2. The pressure in the PLD chamber was 2.7 × 10 -3 Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm 2. The protein digesting capacity of the transferred pepsin was tested by adapting a modified "protein cube" method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.

  15. Rechargeable thin film battery and method for making the same

    DOEpatents

    Goldner, Ronald B.; Liu, Te-Yang; Goldner, Mark A.; Gerouki, Alexandra; Haas, Terry E.

    2006-01-03

    A rechargeable, stackable, thin film, solid-state lithium electrochemical cell, thin film lithium battery and method for making the same is disclosed. The cell and battery provide for a variety configurations, voltage and current capacities. An innovative low temperature ion beam assisted deposition method for fabricating thin film, solid-state anodes, cathodes and electrolytes is disclosed wherein a source of energetic ions and evaporants combine to form thin film cell components having preferred crystallinity, structure and orientation. The disclosed batteries are particularly useful as power sources for portable electronic devices and electric vehicle applications where high energy density, high reversible charge capacity, high discharge current and long battery lifetimes are required.

  16. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    DOEpatents

    Ruffner, Judith A. (Albuquerque, NM); Bullington, Jeff A. (Albuquerque, NM); Clem, Paul G. (Albuquerque, NM); Warren, William L. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Tuttle, Bruce A. (Albuquerque, NM); Schwartz, Robert W. (Seneca, SC)

    1999-01-01

    A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. Pb(Zr.sub.0.4 Ti.sub.0.6)O.sub.3 thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550.degree. C.

  17. Piezoelectric thin films and their applications for electronics

    NASA Astrophysics Data System (ADS)

    Yoshino, Yukio

    2009-03-01

    ZnO and AlN piezoelectric thin films have been studied for applications in bulk acoustic wave (BAW) resonator. This article introduces methods of forming ZnO and AlN piezoelectric thin films by radio frequency sputtering and applications of BAW resonators considering the relationship between the crystallinity of piezoelectric thin films and the characteristics of the BAW resonators. Using ZnO thin films, BAW resonators were fabricated for a contour mode at 3.58 MHz and thickness modes from 200 MHz to 5 GHz. The ZnO thin films were combined with various materials, substrates, and thin films to minimize the temperature coefficient of frequency (TCF). The minimum TCF of BAW resonators was approximately 2 ppm/°C in the range -20 to 80 °C. The electromechanical coupling coefficient (k2) in a 1.9 GHz BAW resonator was 6.9%. Using AlN thin films, 5-20 GHz BAW resonators with an ultrathin membrane were realized. The membrane thickness of a 20 GHz BAW resonator was about 200 nm, k2 was 6.1%, and the quality factor (Q) was about 280. Q decreased with increasing resonant frequency. The value of k2 is almost the same for 5-20 GHz resonators. This result could be obtained by improving the thickness uniformity, by controlling internal stress of thin films, and by controlling the crystallinity of AlN piezoelectric thin film.

  18. CCMR: Synthesis of Nanoporous Gold Thin Films

    NSDL National Science Digital Library

    Thiel, Andrew

    2005-08-17

    Starting with a gold alloy, it is possible to selectively etch away the non-gold element and obtain a tortuous porous network within the gold with pore widths ranging from just 20-4nm. The vast amount of void space makes for large surface areas of approximately 2 m²/g. This new material has found use in such applications as filters, biosensors, chemical catalysts, and ultra-capacitors. Through annealing, the size of these pores can be modified to fit the need of its particular application. Previous research has been done here at Cornell on nanoporous gold in the form of bulk films with of 200?m. However, the behavior of thin films of this material of just 200nm in thickness has not yet been studied extensively. The goal of this project was to come up with a way to create nanoporous gold thin films and to measure the effects of pore coarsening during annealing and the amount of silver remaining in the sample during the etching procedure.

  19. Quantum theory of helimagnetic thin films

    NASA Astrophysics Data System (ADS)

    Diep, H. T.

    2015-01-01

    We study properties of a helimagnetic thin film with a quantum Heisenberg spin model by using the Green's-function method. Surface spin configuration is calculated by minimizing the spin interaction energy. It is shown that the angles between spins near the surface are strongly modified with respect to the bulk configuration. Taking into account this surface spin reconstruction, we calculate self-consistently the spin-wave spectrum and the layer magnetizations as functions of temperature up to the disordered phase. The spin-wave spectrum shows the existence of a surface-localized branch which causes a low surface magnetization. We show that quantum fluctuations give rise to a crossover between the surface magnetization and interior-layer magnetizations at low temperatures. We calculate the transition temperature and show that it depends strongly on the helical angle. Results are in agreement with existing experimental observations on the stability of helical structure in thin films and on the insensitivity of the transition temperature with the film thickness. We also study effects of various parameters such as surface exchange and anisotropy interactions. Monte Carlo simulations for the classical spin model are also carried out for comparison with the quantum theoretical result.

  20. Tribological thin films on steel rolling element bearing surfaces

    Microsoft Academic Search

    Ryan David Evans

    2006-01-01

    Tribological thin films are of interest to designers and end-users of friction management and load transmission components such as steel rolling element bearings. This study sought to reveal new information about the properties and formation of such films, spanning the scope of their technical evolution from natural oxide films, to antiwear films from lubricant additives, and finally engineered nanocomposite metal

  1. Preparation and characterization of spray pyrolysed cobalt oxide thin films

    Microsoft Academic Search

    P. S. Patil; L. D. Kadam; C. D. Lokhande

    1996-01-01

    Cobalt oxide thin films were prepared by the spray pyrolysis method on amorphous glass substrates kept at 300 °C. The films formed were uniform, pin-hole free, and strongly adherent to the substrates. The X-ray diffraction studies revealed that the films consist of Co3O4 oxide phase. The optical and the electrical properties of the film were also studied.

  2. Low-temperature characterization of organic conducting thin films

    NASA Astrophysics Data System (ADS)

    Topasna, Gregory; Topasna, Daniela

    2008-03-01

    Conducting polymer thin films were investigated at low temperatures. We present results for such a spin coated film made of poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) which was tested for temperatures below 20 C. The film was probed over several cycles of cooling then heating. For each cycle the results showed a similar temperature dependent resistance. Such polymer thin films have potential applications as flexible temperature sensors.

  3. Interfacial and thin film chemistry in electron device fabrication

    NASA Astrophysics Data System (ADS)

    Auston, D.; Flynn, G.; Herman, I.; Osgood, R.; Turro, N.

    1992-01-01

    Progress on the Columbia URI program on 'Interfacial and Thin Film Chemistry in Electron Device Fabrication' is reported for the 1986-1991 period. Three broad areas of research included MBE Growth and Devices, Laser Surface Interactions, and Fundamentals of Processing Gas/Surface Interactions. Research in the area of MBE Growth and Devices included Heterostructures Grown by Molecular Beam Epitaxy by Professor Wen Wang and Interface Chemical Modification of Metal on Superconductor-Semiconductor Systems by Professor Ed Yang. Research in the area of Laser Surface Interactions included Laser-Surface Interactions and In Situ Diagnostics of Surface Chemistry During Electronic Processing by Professor Richard Osgood, Jr.; In Situ Optical Diagnostics of Semiconductors Prepared by Laser Chemical Processing and Other Novel Methods by Professor Irving Herman; and Ultrafast Optoelectronic Measurements of Surfaces and Interfaces by Professor David Auston. Research in Fundamentals of Processing Gas/Surface Interactions included Quantum State-Resolved Studies of Gas/Surface Chemical Reactions by Professor George Flynn and Photochemical and Photophysical Probes of Interfaces by Professor Nicholas Turro. Research results of Columbia's Principal Investigators supported by ONR/URI were published in nearly 200 scholarly articles which are listed in this report.

  4. Superconducting properties of Nb thin films deposited on porous silicon templates

    NASA Astrophysics Data System (ADS)

    Trezza, M.; Prischepa, S. L.; Cirillo, C.; Fittipaldi, R.; Sarno, M.; Sannino, D.; Ciambelli, P.; Hesselberth, M. B. S.; Lazarouk, S. K.; Dolbik, A. V.; Borisenko, V. E.; Attanasio, C.

    2008-10-01

    Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10-40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the Hc2?(T ) curvature and oscillations in the field dependence of the superconducting resistive transition width at H ?1 T. This field value is much higher than typical matching fields in perforated superconductors, as a consequence of the small interpore distance.

  5. Development of thin film solar cell based on Cu 2ZnSnS 4 thin films

    Microsoft Academic Search

    Hironori Katagiri; Kotoe Saitoh; Tsukasa Washio; Hiroyuki Shinohara; Tomomi Kurumadani; Shinsuke Miyajima

    2001-01-01

    Cu2ZnSnS4 (hereafter CZTS) thin films were successfully formed by vapor-phase sulfurization of precursors on a soda lime glass substrate (hereafter SLG) and a Mo-coated one (hereafter Mo-SLG). From the optical properties, we estimate the band-gap energy of this thin film as 1.45–1.6eV which is quite close to the optimum value for a solar cell. By using this thin film as

  6. Optical response of YBCO thin films and weak-links

    SciTech Connect

    Osterman, D.P.; Drake, R.; Patt, R.; Track, E.K.; Radparvar, M.; Faris, S.M.

    1989-03-01

    The authors have fabricated films of the high temperature superconductor YBCO and measured their response to optical and infrared radiation. This response to light is manifested by a change in the current-voltage characteristics of YBCO weak-links. They find the change to dependent upon film quality, operating point, light chopping frequency, and temperature. Depending on the type of anneal, the superconducting films exhibit metallic or semiconducting resistivity behavior above T/sub c/. The optical responsivity of semiconducting films is larger than that of metallic films. By further annealing, semiconducting films could be converted into metallic films with a concurrent decrease in their optical reponsivity. Some of the measurements have been performed with the films immersed in superfluid helium to allow the separation of non-equilibrium effects from the equilibrium bolometric response.

  7. Rechargeable thin-film electrochemical generator

    DOEpatents

    Rouillard, Roger (Beloeil, CA); Domroese, Michael K. (South St. Paul, MN); Hoffman, Joseph A. (Minneapolis, MN); Lindeman, David D. (Hudson, WI); Noel, Joseph-Robert-Gaetan (St-Hubert, CA); Radewald, Vern E. (Austin, TX); Ranger, Michel (Lachine, CA); Sudano, Anthony (Laval, CA); Trice, Jennifer L. (Eagan, MN); Turgeon, Thomas A. (Fridley, MN)

    2000-09-15

    An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

  8. Growth process control of pentacene thin films and its application in full organic thin film transistors

    Microsoft Academic Search

    U. Haa; Anja Haase; Hannes Maresch; Barbara Stadlober; Gijnter Leising

    2004-01-01

    Due to its outstanding carrier transport capabilities pentacene is a prominent candidate for the active semiconducting layer in organic thin film transistors. This compound crystallizes in a layered structure with herringbone arrangement within each layer. Pcntacene appears in several polymorphic structures, which differ basically by their c-axis lengths, meaning that the angle at which the molecules adsorb relative to the

  9. Nanostructured Thin Film Electrolyte for Thin Film Solid Oxide Fuel Cells

    E-print Network

    Cho, Sungmee

    2012-10-19

    delta (PBCO), and the electrolyte material as a fluorite structure, Ce0.9Gd0.1O1.95 (CGO or GDC), were achieved for thin film solid oxide fuel cell (TFSOFCs). The VAN structure significantly improves the overall performance of the TFSOFC by increasing...

  10. Process for making dense thin films

    DOEpatents

    Jacobson, Craig P.; Visco, Steven J.; DeJonghe, Lutgard C.

    2005-07-26

    Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for firing of device substrate to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

  11. Nanostructured thin films and their macrobehaviors

    NASA Astrophysics Data System (ADS)

    Lo, Mei-Ling; Liao, Shih-Fang; Lee, Cheng-Chung

    2014-08-01

    The iridescence green band and cyan tail of the wing on Papilio blumei butterfly were investigated. The bi-color phenomenon on the scales of butterfly wings was found and analyzed. The spectral change with thickness of chitin-air layers, width of air hole, total layer numbers and incident angle of light were simulated by FDTD method. 2D photonic-crystal model was applied to explain the change of reflectance spectra and color with angle. The replica of structural color and nanostructured thin films for Papilio blumei butterflies was fabricated successfully by three main techniques, PS spheres bedding, electron-beam gun evaporation and ICP etching.

  12. Photoconductivity in thin films of phthalocyanine

    Microsoft Academic Search

    Francis P Xavier; George J Goldsmith

    1995-01-01

    The photocurrent and electrolyte electromodulation (EEM) spectra of thin films of metal-free phthalocyanine (H2Pc) and of copper phthalocyanine (CuPc) were investigated. The modulation spectra yielded three distinct features around 1·61,\\u000a 2·30 and 2·93 eV for H2Pc and around 1·63, 2·04 and 3·20 eV for CuPc. The spectral dependence maxima of photoconductivity correspond to the modulation\\u000a spectra. These features are interpreted

  13. Casimir Force between Atomically Thin Gold Films

    E-print Network

    M. Boström; C. Persson; Bo E. Sernelius

    2013-02-13

    We have used density functional theory to calculate the anisotropic dielectric functions for ultrathin gold sheets (composed of 1, 3, 6, and 15 atomic layers). Such films are important components in nano-electromechanical systems. When using correct dielectric functions rather than bulk gold dielectric functions we predict an enhanced attractive Casimir-Lifshitz force (at most around 20%) between two atomically thin gold sheets. For thicker sheets the dielectric properties and the corresponding Casimir forces approach those of gold half-spaces. The magnitude of the corrections that we predict should, within the today's level of accuracy in Casimir force measurements, be clearly detectable.

  14. Thin film photovoltaic device with multilayer substrate

    DOEpatents

    Catalano, Anthony W. (Rushland, PA); Bhushan, Manjul (Wilmington, DE)

    1984-01-01

    A thin film photovoltaic device which utilizes at least one compound semiconductor layer chosen from Groups IIB and VA of the Periodic Table is formed on a multilayer substrate The substrate includes a lowermost support layer on which all of the other layers of the device are formed. Additionally, an uppermost carbide or silicon layer is adjacent to the semiconductor layer. Below the carbide or silicon layer is a metal layer of high conductivity and expansion coefficient equal to or slightly greater than that of the semiconductor layer.

  15. Diamond Magnetometry of Superconducting Thin Films

    E-print Network

    Waxman, A; Groswasser, D; Acosta, V M; Bouchard, L -S; Budker, D; Folman, R

    2013-01-01

    In recent years diamond magnetometers based on the nitrogen-vacancy (NV) center have been of considerable interest for magnetometry applications at the nanoscale. An interesting application which is well suited for NV centers is the study of nanoscale magnetic phenomena in superconducting materials. We employ the magnetic sensitivity of the NV centers in diamond to interrogate the magnetic properties of a thin-layer yttrium barium copper oxide (YBCO) superconductor. Using fluorescence-microscopy methods and specially prepared samples, we measure the temperature of phase transition in the layer to be 70.0(2) K, and the first critical field to be 46(4) G. We observe the pinning of the vortices in the layer at 65 K, and estimate their density to be 1.10(2) \\mu m ^{-2}. These measurements are done with a 10 nm thickness layer, so that high spatial resolution may be enabled in the future. Based on these results, we anticipate that this magnetometer could be useful for imaging the structure and dynamics of the vort...

  16. Multiscale modeling on cluster deposited thin film

    NASA Astrophysics Data System (ADS)

    Mizuseki, Hiroshi; Hongo, Kenta; Kawazoe, Yoshiyuki; Wille, Luc T.

    2002-03-01

    Thin film composed of magnetic clusters deposited on various substrates has attracted strong attention both as a new manufacturing technique to realize high density magnetic recording media [1] and to create systems with unique magnetic properties. Since the features of films are influenced by the cluster formation process during the flight path, the relevant physical scale to be studied is as large as centimeters. Moreover, since the behavior of segregation processes on the substrate is not negligible, the relevant smallest physical scale is of the order of 1 nm. In this paper a new model of cluster growth and deposition processes based on a combination of Direct Simulation Monte Carlo (DSMC) [2] and Monte Carlo (MC) methods is introduced to examine the effects of cluster deposition conditions on film formation by an adiabatic expansion process. Several types of size distributions of generated clusters under various conditions are obtained by the present model. The results of the simulations show that the size distribution is strongly related to the experimental conditions and in turn the resulting film properties are varied. [1] H. Mizuseki, M. Ishihara, X. Hu, Y. Kawazoe, and N. Ohta, IEEE Trans. Magn. (1996) 4335. [2] H. Mizuseki, Y. Jin, Y. Kawazoe, and Luc T. Wille, J. Appl. Phys., (2000) 6561.

  17. Electrodeposited CulnSe2 Thin Film Junctions

    NASA Technical Reports Server (NTRS)

    Raffaelle, R. P.; Mantovani, J. G.; Bailey, S. G.; Hepp, A. F.; Gordon, E. M.; Haraway, R.

    1998-01-01

    We have investigated thin films and junctions based on copper indium diselenide (CIS) which have been grown by electrochemical deposition. CIS is a leading candidate for use in polycrystalline thin film photovoltaic solar cells. Electrodeposition is a cost-effective method for producing thin-film CIS. We have produced both p and n type CIS thin films from the same aqueous solution by simply varying the deposition potential. A CIS pn junction was deposited using a step-function potential. Stoichiometry of the single layer films was determined by energy dispersive spectroscopy. Carrier densities of these films increased with deviation from stoichiometry, as determined by the capacitance versus voltage dependence of Schottky contacts. Optical bandgaps for the single layer films as determined by transmission spectroscopy were also found to increase with deviation from stoichiometry. Rectifying current versus voltage characteristics were demonstrated for the Schottky barriers and for the pn junction.

  18. Electrodeposited CuInSe2 Thin Film Junctions

    NASA Technical Reports Server (NTRS)

    Raffaelle, R. P.; Mantovani, J. G.; Bailey, S. G.; Hepp, A. F.; Gordon, E. M.; Haraway, R.

    1997-01-01

    We have investigated thin films and junctions based on copper indium diselenide (CIS) which have been grown by electrochemical deposition. CIS is a leading candidate for use in polycrystalline thin film photovoltaic solar cells. Electrodeposition is a cost-effective method for producing thin-film CIS. We have produced both p and n type CIS thin films from the same aqueous solution by simply varying the deposition potential. A CIS pn junction was deposited using a step-function potential. Stoichiometry of the single layer films was determined by energy dispersive spectroscopy. Carrier densities of these films increased with deviation from stoichiometry, as determined by the capacitance versus voltage dependence of Schottky contacts. Optical bandgaps for the single layer films as determined by transmission spectroscopy were also found to increase with deviation from stoichiometry. Rectifying current versus voltage characteristics were demonstrated for the Schottky barriers and for the pn junction.

  19. The role of microstructural phenomena in magnetic thin films

    SciTech Connect

    Laughlin, D.E.; Lambeth, D.N.

    1992-01-01

    The subject is germane to magnetic recording media. Results during the first 2 years are presented under the following headings: atomic resolution TEM of CoNiCr films; CoNiCr and CoCrTa thin films; development of texture; and CoSm/Cr thin films. The HREM results showed that defects in Co-based films may be responsible for higher coercivity. Findings are presented on the effects of Cr interlayers on the microstructure of the second Co-based film in Co/Cr/Co/Cr multilayer films. Proposed research plans are outlined.

  20. PV prospects: thinPV prospects: thin--film cellsfilm cells Si cell costs

    E-print Network

    Pulfrey, David L.

    of the CdS film · The role of the ZnO/ITO layers · Replacement of CdS/ZnO/ITO with a Schottky barrier Noufi1 PV prospects: thinPV prospects: thin--film cellsfilm cells LECTURE 8 · Si cell costs · optimizing conversion efficiency · thin-film cells · Schottky-barrier theory #12;2 2 Silicon materialSilicon material X

  1. Characterization of thin-film thickness

    NASA Astrophysics Data System (ADS)

    Pourjamal, Sara; Mäntynen, Henrik; Jaanson, Priit; Rosu, Dana Maria; Hertwig, Andreas; Manoocheri, Farshid; Ikonen, Erkki

    2014-12-01

    Analysis methods and instrumentation for obtaining optical parameters and thickness profiles of thin-film samples from spectrophotometric and ellipsometric measurements are presented. Measured samples include thermally grown and evaporated SiO2 on a silicon substrate and a polymer photoresist layer on silicon. Experimental results at multiple sample positions give the thickness uniformity and optical constants of thin films. The thickness results obtained with spectrophotometry and ellipsometry agree within 1 nm for the 300 nm thick layer of SiO2 on silicon. For the 1600 nm thick resist sample the agreement of the measurement methods is within 8 nm. For the sample with a nominally 6000 nm thick layer of SiO2 on silicon, there is a deviation of ˜100 nm between the spectrophotometry and ellipsometry results. As an application, the optical parameters of a SiO2 layer on an induced junction silicon photodiode are determined by spectrophotometry and are used to confirm earlier values and uncertainties of the SiO2 refractive index and layer thickness non-uniformity.

  2. Apparatus for laser assisted thin film deposition

    DOEpatents

    Warner, Bruce E. (Pleasanton, CA); McLean, II, William (Oakland, CA)

    1996-01-01

    A pulsed laser deposition apparatus uses fiber optics to deliver visible output beams. One or more optical fibers are coupled to one or more laser sources, and delivers visible output beams to a single chamber, to multiple targets in the chamber or to multiple chambers. The laser can run uninterrupted if one of the deposition chambers ceases to operate because other chambers can continue their laser deposition processes. The laser source can be positioned at a remote location relative to the deposition chamber. The use of fiber optics permits multi-plexing. A pulsed visible laser beam is directed at a generally non-perpendicular angle upon the target in the chamber, generating a plume of ions and energetic neutral species. A portion of the plume is deposited on a substrate as a thin film. A pulsed visible output beam with a high pulse repetition frequency is used. The high pulse repetition frequency is greater than 500 Hz, and more preferably, greater than about 1000 Hz. Diamond-like-carbon (DLC) is one of the thin films produced using the apparatus.

  3. Apparatus for laser assisted thin film deposition

    DOEpatents

    Warner, B.E.; McLean, W. II

    1996-02-13

    A pulsed laser deposition apparatus uses fiber optics to deliver visible output beams. One or more optical fibers are coupled to one or more laser sources, and delivers visible output beams to a single chamber, to multiple targets in the chamber or to multiple chambers. The laser can run uninterrupted if one of the deposition chambers ceases to operate because other chambers can continue their laser deposition processes. The laser source can be positioned at a remote location relative to the deposition chamber. The use of fiber optics permits multi-plexing. A pulsed visible laser beam is directed at a generally non-perpendicular angle upon the target in the chamber, generating a plume of ions and energetic neutral species. A portion of the plume is deposited on a substrate as a thin film. A pulsed visible output beam with a high pulse repetition frequency is used. The high pulse repetition frequency is greater than 500 Hz, and more preferably, greater than about 1000 Hz. Diamond-like-carbon (DLC) is one of the thin films produced using the apparatus. 9 figs.

  4. thin films toward less leakage currents

    NASA Astrophysics Data System (ADS)

    Yao, Zhao; Wang, Cong; Li, Yang; Kim, Hong-Ki; Kim, Nam-Young

    2014-08-01

    To prepare high-density integrated capacitors with low leakage currents, 0.2-?m-thick BaTiO3 thin films were successfully deposited on integrated semiconductor substrates at room temperature by the aerosol deposition (AD) method. In this study, the effects of starting powder size were considered in an effort to remove macroscopic defects. A surface morphology of 25.3 nm and an interface roughness of less than 50 nm were obtained using BT-03B starting powder. The nano-crystalline thin films achieved after deposition were annealed at various temperatures to promote crystallization and densification. Moreover, the influence of rapid thermal annealing process on the surface morphology and crystal growth was evaluated. As the annealing temperature increased from room temperature to 650°C, the root mean square (RMS) roughness decreased from 25.3 to 14.3 nm. However, the surface was transformed into rough performance at 750°C, which agreed well with the surface microstructure trend. Moreover, the crystal growth also reveals the changes in surface morphology via surface energy analysis.

  5. Structural and optical properties of nanoscale Galinobisuitite thin films.

    PubMed

    Abd-Elkader, Omar H; Deraz, N M

    2014-01-01

    Galinobisuitite thin films of (Bi2S3)(PbS) were prepared using the chemical bath deposition technique (CBD). Thin films were prepared by a modified chemical deposition process by allowing the triethanolamine (TEA) complex of Bi(3+) and Pb(2+) to react with S(2)- ions, which are released slowly by the dissociation of the thiourea (TU) solution. The films are polycrystalline and the average crystallite size is 35 nm. The composition of the films was measured using the atomic absorption spectroscopy (AAS) technique. The films are very adherent to the substrates. The crystal structure of Galinobisuitite thin films was calculated by using the X-ray diffraction (XRD) technique. The surface morphology and roughness of the films were studied using scanning electron microscopes (SEM), transmission electron microscopes (TEM) and stylus profilers respectively. The optical band gaps of the films were estimated from optical measurements. PMID:24473136

  6. Structural and Optical Properties of Nanoscale Galinobisuitite Thin Films

    PubMed Central

    Abd-Elkader, Omar H.; Deraz, N. M.

    2014-01-01

    Galinobisuitite thin films of (Bi2S3)(PbS) were prepared using the chemical bath deposition technique (CBD). Thin films were prepared by a modified chemical deposition process by allowing the triethanolamine (TEA) complex of Bi3+ and Pb2+ to react with S2? ions, which are released slowly by the dissociation of the thiourea (TU) solution. The films are polycrystalline and the average crystallite size is 35 nm. The composition of the films was measured using the atomic absorption spectroscopy (AAS) technique. The films are very adherent to the substrates. The crystal structure of Galinobisuitite thin films was calculated by using the X-ray diffraction (XRD) technique. The surface morphology and roughness of the films were studied using scanning electron microscopes (SEM), transmission electron microscopes (TEM) and stylus profilers respectively. The optical band gaps of the films were estimated from optical measurements. PMID:24473136

  7. Applications of Thin Film Thermocouples for Surface Temperature Measurement

    NASA Technical Reports Server (NTRS)

    Martin, Lisa C.; Holanda, Raymond

    1994-01-01

    Thin film thermocouples provide a minimally intrusive means of measuring surface temperature in hostile, high temperature environments. Unlike wire thermocouples, thin films do not necessitate any machining of the surface, therefore leaving intact its structural integrity. Thin films are many orders of magnitude thinner than wire, resulting in less disruption to the gas flow and thermal patterns that exist in the operating environment. Thin film thermocouples have been developed for surface temperature measurement on a variety of engine materials. The sensors are fabricated in the NASA Lewis Research Center's Thin Film Sensor Lab, which is a class 1000 clean room. The thermocouples are platinum-13 percent rhodium versus platinum and are fabricated by the sputtering process. Thin film-to-leadwire connections are made using the parallel-gap welding process. Thermocouples have been developed for use on superalloys, ceramics and ceramic composites, and intermetallics. Some applications of thin film thermocouples are: temperature measurement of space shuttle main engine turbine blade materials, temperature measurement in gas turbine engine testing of advanced materials, and temperature and heat flux measurements in a diesel engine. Fabrication of thin film thermocouples is described. Sensor durability, drift rate, and maximum temperature capabilities are addressed.

  8. Biohybrid thin films for measuring contractility in engineered cardiovascular muscle

    E-print Network

    Parker, Kevin Kit

    tissue biomechanics Cardiac tissue engineering Cardiomyocyte Smooth muscle cell Mechanical properties a b anisotropic muscle tissue cultured on a flexible synthetic polymer thin film. Cardiac muscle engineered reported on a muscular thin film (MTF) technique that enables cardiac muscle monolayers, engineered

  9. Thin film knitting pattern morphology from a miktoarm star terpolymer.

    PubMed

    Choi, Hong Kyoon; Nunns, Adam; Sun, Xue Yin; Manners, Ian; Ross, Caroline A

    2014-04-23

    Thin film knitting pattern from a miktoarm star terpolymer is demonstrated. Such structures have been predicted but not observed in bulk or thin film form. The knitting pattern exhibits well organized periodic structures consisting of undulating lamellae and alternating cylinders, with well-defined defects that result in sharp 90° bends and T junctions. PMID:24469920

  10. A survey of thin-film solar photovoltaic industry & technologies

    E-print Network

    Grama, Sorin

    2007-01-01

    A new type of solar cell technology using so-called thin-film solar photovoltaic material has the potential to make a great impact on our lives. Because it uses very little or no silicon at all, thin- film (TF) solar ...

  11. Carbon monoxide sensitivity of vacuum deposited polyaniline semiconducting thin films

    Microsoft Academic Search

    V. Dixit; S. C. K. Misra; B. S. Sharma

    2005-01-01

    By utilizing the semiconducting polymeric thin films on various substrates a new simple and quick technique has been developed for sensing carbon monoxide gas. The thin films of polyaniline were prepared by vacuum deposition. The particular doping combination in the polymer makes the sensor specific for detection of CO. Polyaniline was prepared by copolymerization of aniline and formaldehyde. Metal halides

  12. AFRL thin-film photovoltaics DSX and roadrunner flight experiments

    Microsoft Academic Search

    P. Hausgen; J. E. Granata; P. Tlomak; J. Jones; S. Enger; B. Zuckermandel

    2005-01-01

    Thin-film solar cells offer great promise for increasing the capability of future spacecraft. While their efficiencies are low compared to state of the art crystalline solar cells, they have unique attributes that make them very attractive for space use. These attributes include flexibility, low mass, and low cost production. The attractive attributes of thin-film solar cells will go untapped until

  13. Strong photoluminescence of nanostructured crystalline tungsten oxide thin films

    E-print Network

    Gao, Hongjun

    Strong photoluminescence of nanostructured crystalline tungsten oxide thin films M. Feng, A. L. Pan is observed in nanostructured crystalline tungsten oxide thin films that are prepared by thermal evaporation. Compared with the complete absence of emission of bulk phase tungsten oxide powder under the same

  14. Advanced electrochromic devices based on WO 3 thin films

    Microsoft Academic Search

    S Papaefthimiou; G Leftheriotis; P Yianoulis

    2001-01-01

    We present work on the development of advanced materials suitable for use as electrochromic thin films (EC), ion storage layers and transparent conductors (TC) in electrochromic devices. These thin film layers were prepared in our laboratory by thermal evaporation and electron gun deposition. They were incorporated into electrochromic devices, which were subsequently characterized by optical and electrochemical techniques such as

  15. Recording performance of longitudinal barium ferrite thin film media

    Microsoft Academic Search

    Xiaoyu Sui; A. Singh; Yinglian Chen; D. N. Lambeth; M. K. Krydeer

    1995-01-01

    The high density recording characteristics of barium ferrite thin film media have been investigated. High levels of overwrite are achieved. Media microstructures have been identified to have a close relation to the noise behavior in the barium ferrite thin films. A linear increase in noise spectra is observed, indicating the existence of transition noise. In addition, positive ?M peaks are

  16. CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS

    E-print Network

    Hart, Gus

    CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS by David T. Oliphant. Woolley Dean, College of Physical and Mathematical Sciences #12;ABSTRACT CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS David T. Oliphant Department of Physics and Astronomy

  17. Tools to Synthesize the Learning of Thin Films

    ERIC Educational Resources Information Center

    Rojas, Roberto; Fuster, Gonzalo; Slusarenko, Viktor

    2011-01-01

    After a review of textbooks written for undergraduate courses in physics, we have found that discussions on thin films are mostly incomplete. They consider the reflected and not the transmitted light for two instead of the four types of thin films. In this work, we complement the discussion in elementary textbooks, by analysing the phase…

  18. Laminates of Thin Ferromagnetic Films for Microwave Applications

    Microsoft Academic Search

    K. N. Rozanov; I. T. Iakubov; A. N. Lagarkov; S. A. Maklakov; A. V. Osipov; D. A. Petrov; L. Ryzhikov; M. V. Sedova; S. N. Starostenko

    2007-01-01

    Thin ferromagnetic films are known to exhibit the highest possible microwave permeability of known magnetic materials. Magnetic materials with high microwave magnetic performance are useful for many technical applications. However, bulk rather than planar materials are frequently needed for the applications. Bulk materials with high microwave permeability may be produced as laminated structures of thin ferromagnetic films, possibly patterned. The

  19. XPS depth profile study of sprayed CZTS thin films

    NASA Astrophysics Data System (ADS)

    Deepu, D. R.; Rajeshmon, V. G.; Kartha, C. Sudha; Vijayakumar, K. P.

    2014-04-01

    XPS depth profile studies were carried out to analyze the composition and stoichiometry of sprayed CZTS thin films giving an efficiency of 1.85% in CZTS based thin film solar cell. Surface layers were nearly stoichiometric (Cu:Zn:Sn:S=2:1:1:4) whereas the inner layers were found to be Copper rich in composition making it electrically more conductive.

  20. Texture control of fluorine-doped tin oxide thin film

    Microsoft Academic Search

    Chang-Yeoul Kim; Doh-Hyung Riu

    2011-01-01

    The texture control of transparent oxide thin film, the crystalline orientation, is very important, because it is related to the electrical resistivity and the optical transparency. It is known that the crystal orientation could be controlled by varying precursor source, gas flow rate, and deposition temperature. We deposited fluorine-doped tin oxide (FTO) thin film on aluminoborosilicate glass by spraying water-based

  1. AFRL Thin Film Solar Cell Development and Upcoming Flight Experiments

    Microsoft Academic Search

    Jennifer E. Granata; Paul E. Hausgen; Donna Senft; Pawel Tlomak; John Merrill

    2005-01-01

    The many advantages of thin film solar cells, namely flexibility, high radiation resistance, low mass, and low cost production, will go untapped until space environmental effects on them are well understood, which requires on-orbit testing. In response to the need to perform on-orbit testing of thin film solar cells, the Space Vehicles Directorate of the Air Force Research Laboratory (AFRL)

  2. STRESS-INDUCED PERIODIC FRACTURE PATTERNS IN THIN FILMS Alex A. Volinsky1

    E-print Network

    Volinsky, Alex A.

    STRESS-INDUCED PERIODIC FRACTURE PATTERNS IN THIN FILMS Alex A. Volinsky1 , Neville R. Moody2 applied stresses in thin films can cause film fracture. In the case of compressive stress thin film stress a network of through- thickness cracks forms in thin films. Excessive biaxial residual stress

  3. Development of a thin film solid state gaseous HCl sensor

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The selection of materials to develop a thin film HCl sensor is discussed. Data were primarily concerned with chemical and physical properties of the film and with electrical properties which exhibit and enhance electrical response when HCl is absorbed on the film surface. Techniques investigated for enhancing electrical response include changing conditions for growing films, adding impurities to the film, changing ambient light intensity, and altering the ambient temperature of the sensing element.

  4. Physical properties in thin films of iron oxides.

    SciTech Connect

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Girata, D.; Morales, A. L.; Hoffmann, A.; Materials Science Division; Univ. de Antioquia

    2008-01-01

    We have grown hematite ({alpha}-Fe{sub 2}O{sub 3}) thin films on stainless steel substrates and magnetite (Fe{sub 3}O{sub 4}) thin films on (0 0 1)-Si single crystal substrates by a RF magnetron sputtering process. {alpha}-Fe{sub 2}O{sub 3} thin films were grown in an Ar atmosphere at substrate temperatures around 400 C, and Fe{sub 3}O{sub 4} thin films in an Ar/O{sub 2} reactive atmosphere at substrate temperatures around 500 C. Conversion electron Moessbauer (CEM) spectra of {alpha}-Fe{sub 2}O{sub 3} thin films exhibit values for hyperfine parameter characteristic of the hematite stoichiometric phase in the weak ferromagnetic state [R.E. Vandenberghe, in: Moessbauer Spectroscopy and Applications in Geology, University Gent, Belgium, 1990. [1

  5. Anomalies of piezoelectric coefficients in barium titanate thin films

    NASA Astrophysics Data System (ADS)

    Shirokov, Vladimir; Kalinchuk, Valery; Shakhovoy, Roman; Yuzyuk, Yury

    2014-11-01

    Modeling of electromechanical devices involves the use of different material coefficients, whose measurement is a difficult task, especially when the problem concerns thin films. Required coefficients of thin films could be found theoretically, using known values of the bulk constants. Electromechanical coefficients of barium titanate thin films are still unknown; therefore, it is expedient to carry out their calculations. We give here the full set of electromechanical coefficients of barium titanate thin films for the whole range of technologically available misfit strains. In the present paper, piezoelectric coefficients as functions of a misfit strain were calculated. It was revealed that piezoelectric coefficients exhibit anomalies at phase boundaries and inside the monoclinic r-phase as well. The obtained results allow finding the required values of the thin-film parameters, varying the misfit strain.

  6. Pulsed laser deposition of nanoporous cobalt thin films.

    PubMed

    Jin, Chunming; Nori, Sudhakar; Wei, Wei; Aggarwal, Ravi; Kumar, Dhananjay; Narayan, Roger J

    2008-11-01

    Nanoporous cobalt thin films were deposited on anodized aluminum oxide (AAO) membranes at room temperature using pulsed laser deposition. Scanning electron microscopy demonstrated that the nanoporous cobalt thin films retained the monodisperse pore size and high porosity of the anodized aluminum oxide substrates. Temperature- and field-dependent magnetic data obtained between 10 K and 350 K showed large hysteresis behavior in these materials. The increase of coercivity values was larger for nanoporous cobalt thin films than for multilayered cobalt/alumina thin films. The average diameter of the cobalt nanograins in the nanoporous cobalt thin films was estimated to be approsimately 5 nm for blocking temperatures near room temperature. These results suggest that pulsed laser deposition may be used to fabricate nanoporous magnetic materials with unusual properties for biosensing, drug delivery, data storage, and other technological applications. PMID:19198344

  7. Method of producing solution-derived metal oxide thin films

    DOEpatents

    Boyle, Timothy J. (Albuquerque, NM); Ingersoll, David (Albuquerque, NM)

    2000-01-01

    A method of preparing metal oxide thin films by a solution method. A .beta.-metal .beta.-diketonate or carboxylate compound, where the metal is selected from groups 8, 9, 10, 11, and 12 of the Periodic Table, is solubilized in a strong Lewis base to form a homogeneous solution. This precursor solution forms within minutes and can be deposited on a substrate in a single layer or a multiple layers to form a metal oxide thin film. The substrate with the deposited thin film is heated to change the film from an amorphous phase to a ceramic metal oxide and cooled.

  8. Functional properties of nickel cobalt oxide thin films

    Microsoft Academic Search

    F. Iacomi; G. Calin; C. Scarlat; M. Irimia; C. Doroftei; M. Dobromir; G. G. Rusu; N. Iftimie; A. V. Sandu

    2011-01-01

    Cobalt–nickel oxide films of known stoichiometry (x=Ni\\/(Co+Ni)=0.30–0.63) were deposited on glass slides by using a spin-coating method and were UV irradiated for 2h. The structure and morphology of thin films evidenced nanocrystalline spinel structures. Thin films with x=0.63–0.5 have a mixed phase structure and good sensing properties for ethanol. Thin films with x=0.30–0.40 have a single spinel phase, are ferrimagnetic

  9. Controlled nanostructuration of polycrystalline tungsten thin films

    SciTech Connect

    Girault, B. [Institut P' (UPR 3346 CNRS), Universite de Poitiers, ENSMA, Bd Pierre et Marie Curie, 86962 Futuroscope Cedex (France); Institut de Recherche en Genie Civil et Mecanique (UMR CNRS 6183), LUNAM Universite, Universite de Nantes, Centrale Nantes, CRTT, 37 Bd de l'Universite, BP 406, 44602 Saint-Nazaire Cedex (France); Eyidi, D.; Goudeau, P.; Guerin, P.; Bourhis, E. Le; Renault, P.-O. [Institut P' (UPR 3346 CNRS), Universite de Poitiers, ENSMA, Bd Pierre et Marie Curie, 86962 Futuroscope Cedex (France); Sauvage, T. [CEMHTI/CNRS (UPR 3079 CNRS), Universite d'Orleans, 3A rue de la Ferollerie, 45071 Orleans Cedex 2 (France)

    2013-05-07

    Nanostructured tungsten thin films have been obtained by ion beam sputtering technique stopping periodically the growing. The total thickness was maintained constant while nanostructure control was obtained using different stopping periods in order to induce film stratification. The effect of tungsten sublayers' thicknesses on film composition, residual stresses, and crystalline texture evolution has been established. Our study reveals that tungsten crystallizes in both stable {alpha}- and metastable {beta}-phases and that volume proportions evolve with deposited sublayers' thicknesses. {alpha}-W phase shows original fiber texture development with two major preferential crystallographic orientations, namely, {alpha}-W<110> and unexpectedly {alpha}-W<111> texture components. The partial pressure of oxygen and presence of carbon have been identified as critical parameters for the growth of metastable {beta}-W phase. Moreover, the texture development of {alpha}-W phase with two texture components is shown to be the result of a competition between crystallographic planes energy minimization and crystallographic orientation channeling effect maximization. Controlled grain size can be achieved for the {alpha}-W phase structure over 3 nm stratification step. Below, the {beta}-W phase structure becomes predominant.

  10. Incipient CdS thin film formation.

    PubMed

    Kostoglou, M; Andritsos, N; Karabelas, A J

    2003-07-01

    The quality of a final thin film is essentially determined by the processes taking place at incipient CdS deposition, which in turn are strongly influenced by the physicochemical properties of the substrate and liquid in contact. SEM pictures of deposits formed through steady flow of a supersaturated (with respect to CdS) solution suggest that initially nuclei are continuously generated on the substrate and grow as discrete "surface" particles. With time, these particles tend to "coalesce" with neighboring ones, while new nuclei keep forming and growing, leading to the formation of a coherent film. There is evidence that similar growth patterns prevail in CdS deposition via the chemical bath deposition (CBD) process. Based on experimental observations, a simple model is developed, which is capable of predicting macroscopically determined film characteristics such as the temporal thickness evolution including the "induction period." Two cases of the growth pattern are examined theoretically; one based on instantaneous surface nucleation (due to its simplicity) and another with a constant surface nucleation rate, which appears to be closer to experimental observations. PMID:12804900

  11. Fracture of nanoporous organosilicate thin films

    NASA Astrophysics Data System (ADS)

    Gage, David Maxwell

    Nanoporous organosilicate thin films are attractive candidates for a number of emerging technologies, ranging from biotechnology to optics and microelectronics. However, integration of these materials is challenged by their fragile nature and susceptibility to mechanical failure. Debonding and cohesive cracking of the organosilicate film are principal concerns that threaten the reliability and yield of device structures. Despite the intense interest in these materials, there is currently a need for greater understanding of the relationship between glass structure and thermomechanical integrity. The objective of this research was to investigate strategies for improving mechanical performance through variations in film chemistry, process conditions, and pore morphology. Several approaches to effecting improvements in elastic and fracture properties were examined in depth, including post-deposition curing, molecular reinforcement using hydrocarbon network groups, and manipulation of pore size and architecture. Detailed structural characterization was employed along with quantitative fracture mechanics based testing methods. It was shown that ultra-violet irradiation and electron bombardment post-deposition treatments can significantly impact glass structure in ways that cannot be achieved through thermal activation alone. Both techniques demonstrated high porogen removal efficiency and enhanced the glass matrix through increased network connectivity and local bond rearrangements. The increases in network connectivity were achieved predominantly through the replacement of terminal groups, particularly methyl and silanol groups, with Si-O network bonds. Nuclear magnetic resonance spectroscopy was shown to be a powerful and quantitative method for gaining new insight into the underlying cure reactions and mechanisms. It was demonstrated that curing leads to significant progressive enhancement of elastic modulus and adhesive fracture energies due to increased network bond density that results from higher network connectivity along with slight densification of the film. At the same time, the curing produced only a modest progressive increase in dielectric constant, indicating that ultra-violet and electron beam curing show great promise for the processing of low-k and ultra low-k organosilicate films. However, some general limitations of the curing processes were also discovered. In particular, the cohesive fracture energies of organosilicate films were found to be largely insensitive to curing. This was shown to be due to a crack meandering phenomenon in which the crack undergoes small-scale deflections toward local regions of free volume and reduced network bond density, thereby mitigating the effects of curing. Additionally, neither ultra-violet nor electron-beam curing were successful at improving adhesion at the lower film to barrier interface, suggesting little or no curing effects at the bottom portion of the dielectric layer. Sol-gel condensation of carbon-bridged organosilanes was used to prepare low-k films that feature hydrocarbon network bonds in lieu of terminal organic substituents. The hydrocarbon ligaments served to preserve connectivity and reinforce the glass network, resulting in remarkable improvements in elastic modulus and fracture resistance relative to competing carbon-doped oxides or SSQ derived materials of the same dielectric constant. The improvements in fracture resistance were rationalized in terms of a bridging contribution during stretching and rupture of the hydrocarbon chains that was found to scale with the length of the bridging hydrocarbon group. Additionally, the Si-C bonds in the bridged organosilicates made these films less prone to moisture assisted cracking than their silica-based and SSQ counterparts. The bridged organosilicate films demonstrated outstanding mechanical properties even at high porosity, making them excellent candidates for ultra low-k porous applications. The impact of pore morphology on the fracture of nanoporous films was also examined. For a given pore generating sche

  12. Enhanced sputtering from nanoparticles and thin films: Size effects

    NASA Astrophysics Data System (ADS)

    Järvi, T. T.; Pakarinen, J. A.; Kuronen, A.; Nordlund, K.

    2008-04-01

    Sputtering of gold nanoparticles and nanometer-thin films under 25 keV gallium-ion bombardment is shown, using molecular-dynamics simulations, to be significantly enhanced compared to bulk. The highest yield, about three times that of bulk gold, occurs for particles of about 8 nm in diameter. For thin films, the maximal yield is obtained for roughly 3 nm thick films. A model based on the work of Sigmund is presented to explain the size-dependence.

  13. Ferroelectric Thin-Film Capacitors for Flexible Nonvolatile Memory Applications

    Microsoft Academic Search

    Jonghyun Rho; Sang Jin Kim; Wook Heo; Nae-Eung Lee; Hwan-Soo Lee; Jong-Hyun Ahn

    2010-01-01

    This letter reports the fabrication of PbZrxTi1-xO3 (PZT) thin-film capacitors on flexible plastic substrates. The PZT film was formed on a wafer using a sol-gel method and transferred to a thin plastic substrate using an elastomeric stamp. The PZT film on the plastic substrate showed a well-saturated hysteresis loop with a Pr of ~ 20?C\\/cm2 and a Vc of ~1.1

  14. Uniaxial anisotropy in magnetite thin film—Magnetization studies

    Microsoft Academic Search

    A. Wiechec; J. Korecki; B. Handke; Z. Kakol; D. Owoc; D. A. Antolak; A. Kozlowski

    2006-01-01

    Magnetization and electrical resistivity measurements have been performed on a stoichiometric single crystalline magnetite Fe3O4 thin film (thickness of ca. 500nm) MBE deposited on MgO (100) substrate. The aim of these studies was to check the influence of preparation method and sample form (bulk vs. thin film) on magnetic anisotropy properties in magnetite. The film magnetization along ?001? versus applied

  15. Thin film adhesion by nanoindentation-induced superlayers. Final report

    SciTech Connect

    Gerberich, William W.; Volinsky, A.A.

    2001-06-01

    This work has analyzed the key variables of indentation tip radius, contact radius, delamination radius, residual stress and superlayer/film/interlayer properties on nanoindentation measurements of adhesion. The goal to connect practical works of adhesion for very thin films to true works of adhesion has been achieved. A review of this work titled ''Interfacial toughness measurements of thin metal films,'' which has been submitted to Acta Materialia, is included.

  16. Electrochromism in spray deposited iridium oxide thin films

    Microsoft Academic Search

    P. S. Patil; R. K. Kawar; S. B. Sadale

    2005-01-01

    Electrochromic iridium oxide thin films were deposited onto fluorine doped tin oxide coated glass substrates from an aqueous iridium chloride solution by pneumatic spray pyrolysis technique. The as-deposited samples were X-ray amorphous. The electrochromic properties of thin films were studied in an aqueous electrolyte (0.5N H2SO4) using cyclic voltammetry (CV), chronoamperometry (CA) and spectrophotometry. Iridium oxide films show pronounced anodic

  17. Thin film coatings for space electrical power system applications

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1988-01-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  18. Thin film coatings for space electrical power system applications

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1989-01-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  19. Interconnected Si nanocrystals forming thin films with controlled bandgap values

    SciTech Connect

    Nychyporuk, T.; Zakharko, Yu.; Lysenko, V.; Lemiti, M. [Lyon Institut of Nanotechnologies (INL), CNRS UMR-5270, University of Lyon, INSA de Lyon, 7 avenue Jean Capelle, Bat. Blaise Pascal, 69621 Villeurbanne Cedex (France)

    2009-08-24

    Interconnected Si nanocrystals forming homogeneous thin films with controlled bandgap values from 1.2 to 2.9 eV were formed by pulsed plasma enhanced chemical vapor deposition technique under dusty plasma conditions. The chosen values of plasma duration time correspond to specific phases of the dust nanoparticle growth. Structural and optical properties of the deposited nanostructured films are described in details. These nanocrystalline Si thin films seem to be promising candidates for all-Si tandem solar cell applications.

  20. Thickness-dependent properties of sprayed cobalt oxide thin films

    Microsoft Academic Search

    L. D Kadam; P. S Patil

    2001-01-01

    Cobalt oxide thin films with variable thickness were deposited by pneumatic spray pyrolysis technique (PSPT) onto the amorphous glass substrates kept at 300°C. The quantity of cobalt chloride solution was varied to obtain cobalt oxide thin films with thickness ranging from 0.9 to 1.7?m. The effect of film thickness on structural, electrical and optical properties was studied. The X-ray diffraction

  1. Zinc Oxide Thin Films by Spray Pyrolysis Method

    Microsoft Academic Search

    K. Krunks; O. Bijakina; V. Mikli; T. Varema; E. Mellikov

    1999-01-01

    ZnO thin films were deposited by spraying of zinc acetate solution onto heated glass substrates at 670K. Highly textured in the (002) direction undoped ZnO films, exhibiting exciton emission bands in photoluminescence spectra at 8K, were grown. The initial stages of the thin film growth and effect of doping with In, Ce and Eu were studied. A spraying time of

  2. Structural and photoluminescent properties of TiN thin films

    NASA Astrophysics Data System (ADS)

    Solovan, M. N.; Brus, V. V.; Maryanchuk, P. D.; Fodchuk, I. M.; Lorents, V. M.; Sletov, A. M.; Sletov, M. M.; Gluba, M.

    2014-11-01

    Structural and photoluminescent properties of TiN thin films deposited by dc reactive magnetron sputtering are studied. It is found that TiN thin films are polycrystalline with a grain size of ˜15 nm and have a NaCl-type cubic crystal structure with a lattice constant of 0.42 nm. The TiN films under study exhibit photoluminescence in the spectral range h ? ? 2.1-3.4 eV at 300 K.

  3. High-Temperature Superconducting/Ferroelectric, Tunable Thin-Film Microwave Components

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.

    1998-01-01

    At the NASA Lewis Research Center, ferroelectric films such as SrTiO3 and Ba(sub x)Sr(sub 1-x)TiO3, are being used in conjunction with YBa(sub 2)Cu(sub 3)O(sub 7-delta) high-temperature superconducting thin films to fabricate tunable microwave components such as filters, phase shifters, and local oscillators. These structures capitalize on the variation of the dielectric constant of the ferroelectric film upon the application of a direct-current electric field, as well as on the low microwave losses of high-temperature superconductors relative to their conventional conductor counterparts. For example, the surface resistance for a YBa(sub 2)Cu(sub 3)O(sub 7-delta) thin film at 10 GHz and 77 K is more than two orders of magnitude lower than that of copper or gold at the same temperature and frequency. SrTiO3 and Ba(sub x)Sr(sub 1-x)TiO3 films are used because their crystal structure and lattice parameters are similar to those of YBa(sub 2)Cu(sub 3)O(sub 7-delta), thus enabling the growth of highly textured YBa(sub 2)Cu(sub 3)O(sub 7-delta) films with high critical current densities (i.e., greater than 1 MA/sq cm) on the underlying ferroelectric film, or alternatively, of highly textured ferroelectric film on the underlying YBa(sub 2)Cu(sub 3)O(sub 7-delta) film.

  4. Transferable and flexible thin film devices for engineering applications

    NASA Astrophysics Data System (ADS)

    Mutyala, Madhu Santosh K.; Zhou, Jingzhou; Li, Xiaochun

    2014-05-01

    Thin film devices can be of significance for manufacturing, energy conversion systems, solid state electronics, wireless applications, etc. However, these thin film sensors/devices are normally fabricated on rigid silicon substrates, thus neither flexible nor transferrable for engineering applications. This paper reports an innovative approach to transfer polyimide (PI) embedded thin film devices, which were fabricated on glass, to thin metal foils. Thin film thermocouples (TFTCs) were fabricated on a thin PI film, which was spin coated and cured on a glass substrate. Another layer of PI film was then spin coated again on TFTC/PI and cured to obtain the embedded TFTCs. Assisted by oxygen plasma surface coarsening of the PI film on the glass substrate, the PI embedded TFTC was successfully transferred from the glass substrate to a flexible copper foil. To demonstrate the functionality of the flexible embedded thin film sensors, they were transferred to the sonotrode tip of an ultrasonic metal welding machine for in situ process monitoring. The dynamic temperatures near the sonotrode tip were effectively measured under various ultrasonic vibration amplitudes. This technique of transferring polymer embedded electronic devices onto metal foils yield great potentials for numerous engineering applications.

  5. Integrated thin film cadmium sulfide solar cell module

    NASA Technical Reports Server (NTRS)

    Mickelsen, R. A.; Abbott, D. D.

    1971-01-01

    The design, development, fabrication and tests of flexible integrated thin-film cadmium sulfide solar cells and modules are discussed. The development of low cost and high production rate methods for interconnecting cells into large solar arrays is described. Chromium thin films were applied extensively in the deposited cell structures as a means to: (1) achieve high adherence between the cadmium sulfide films and the vacuum-metallized copper substrates, (2) obtain an ohmic contact to the cadmium sulfide films, and (3) improve the adherence of gold films as grids or contact areas.

  6. Effect of current injection into thin-film Josephson junctions

    NASA Astrophysics Data System (ADS)

    Kogan, V. G.; Mints, R. G.

    2014-11-01

    New thin-film Josephson junctions have recently been tested in which the current injected into one of the junction banks governs Josephson phenomena. One thus can continuously manage the phase distribution at the junction by changing the injected current. A method of calculating the distribution of injected currents is proposed for a half-infinite thin-film strip with source-sink points at arbitrary positions at the film edges. The strip width W is assumed small relative to ? =2 ?2/d ;? is the bulk London penetration depth of the film material and d is the film thickness.

  7. Thickness measurement of thin films by x-ray absorption

    NASA Astrophysics Data System (ADS)

    Chaudhuri, J.; Shah, S.

    1991-01-01

    An x-ray diffraction method for determining thicknesses of thin films grown on single-crystal substrates is presented. The equations, based on the kinematical theory of x-ray diffraction and the mosaic crystal model, were developed. The thickness of the thin film was computed from the absorption of the integrated diffracted x-ray intensity from the single-crystal substrate. Since the diffracted intensity from the film is not required, the film does not have to be single crystal in nature. Thus, thicknesses of less ordered, polycrystalline, or even amorphous films can be measured with high precision by this technique.

  8. Ferroelectric behavior in bismuth ferrite thin films of different thickness.

    PubMed

    Wu, Jiagang; Wang, John; Xiao, Dingquan; Zhu, Jianguo

    2011-09-01

    The ferroelectric behavior of BiFeO(3) thin films is modified by changing the film thicknesses, where the BiFeO(3) thin films with different thicknesses were grown on SrRuO(3)/Pt/TiO(2)/SiO(2)/Si(100) substrates by radio frequency sputtering. The mixture of (110) and (111) orientations is induced for all BiFeO(3) thin films regardless of their thicknesses, together with the columnar structure and the dense microstructure. Their dielectric behavior is almost independent of the film thickness where all thin films have a low dielectric loss. A giant remanent polarization of 2P(r) ? 156.6-188.8 ?C/cm(2) is induced for the BiFeO(3) thin films in the thickness range of 190-600 nm. As a result, it is an effective way to improve the ferroelectric behavior of the BiFeO(3) thin film by tailoring the film thickness. PMID:21861505

  9. Thin film silicon solar cells on liquid crystal polymer substrate

    Microsoft Academic Search

    Takatoshi Takeda; Michio Kondo; Akihisa Matsuda

    2003-01-01

    We have developed a liquid crystal polymer (LCP) film applicable to the substrate in the roll-to-roll manufacturing of thin film silicon solar cells. LCP film has excellent and balanced properties of high thermal resistance, high dimensional stability and low moisture absorption compared to other super engineering plastics such as PES or PAR. Microcrystalline silicon solar cells with a nip structure

  10. Improved process for making thin-film sodium niobate capacitors

    NASA Technical Reports Server (NTRS)

    Micka, E. Z.

    1968-01-01

    Sodium niobate, formed by high vacuum, flash, and reactive evaporations, has a high dielectric constant and is used as a thin film dielectric in microelectronic capacitors. High purity films are formed from relatively inexpensive, pure starting materials. Crystalline sodium niobate films can be formed on amorphous or crystalline materials.

  11. Graphene-Silica Composite Thin Films as Transparent Conductors

    E-print Network

    or metal oxide films such as indium tin oxide (ITO) or aluminum-doped zinc oxide (AZO).2,7,9-24 HoweverGraphene-Silica Composite Thin Films as Transparent Conductors Supinda Watcharotone, Dmitriy A Transparent and electrically conductive composite silica films were fabricated on glass and hydrophilic Si

  12. Optical pump Terahertz probe transmission spectroscopy of YBCO thin films

    Microsoft Academic Search

    Anna Kristoffersen; John Nam

    2005-01-01

    Our facility uses optical pump THz probe transmission spectroscopy to study the quasiparticle dynamics in Yttrium Barium Copper Oxide (YBCO) thin films. The recovery of the film exhibits two components, a fast response on the order of several ps and a long tail that lasts nanoseconds. In this presentation, the behaviour of the film in both the fast and long

  13. Optimization of Chemical Bath Deposited Cadmium Sulfide Thin Films

    Microsoft Academic Search

    R. C. Weast; Teil B; Verlag Chemie; Lee Chow

    We report the optimization of CdS thin film grown by chemical bath deposition where homogenous reactions are min- imized. The optimum parameters have enabled us to maximize the thickness of the deposited film in a single dip and to grow thicker films by periodically replenishing the concentration of reactants while the substrate remains continuously dipped in the reaction bath. Characterization

  14. Studies on electrochromism of spray pyrolyzed cobalt oxide thin films

    Microsoft Academic Search

    P. S Patil; L. D Kadam; C. D Lokhande

    1998-01-01

    Cobalt oxide thin films were prepared by spray pyrolysis technique on to fluorine doped tin oxide (F.T.O.) coated glass substrates. The electrochromic cell was formed by using these films as working electrodes and the electrochromic characteristics were determined by using cyclic voltammetry and chronoamperometry. The films exhibited anodic electrochromism; changing colour from grey to pale yellow.

  15. The microstructures of organic thin films for transistor applications

    NASA Astrophysics Data System (ADS)

    Yuan, Quan

    Organic semiconductors with conjugated pi-electron systems show great potential for low-cost, large-area electronic applications. Remarkable progress has been achieved in this field in the last two decades. Broader acceptance of organic semiconductors in electronic applications requires development of new materials with high charge carrier mobility and chemical stability in environmental conditions. A smart material design relies on a thorough understanding of the materials structure and property relationship. The organic thin film transistor (OTFT) is the core of many electronic applications. This thesis work is focused on understanding the correlation between microstructures and electronic properties for vacuum deposited oligomer thin films for transistor applications. Most previous structural characterizations were performed on bulk crystals, and the obtained bulk structures were correlated with thin film charge transport properties. However, charge transportation in OTFT mainly takes place in the first few monolayers near the dielectric/semiconductor interface. The microstructures of thin films near the channel region may be significantly different from bulk crystal structures. For example, in pentacene thin films the film structure is known to be significantly different from its bulk structure. In order to directly correlate molecular packing with thin film charge transport properties, it is crucial to obtain the detailed structure of the organic semiconductor in the thin films in contact with the dielectric surface. In this work, we selected aromatic cores which have already demonstrated high OTFT performance, and systematically introduced changes to the molecular structure. We studied changes in OTFT thin film microstructures and charge transport properties. In order to learn the detailed structure for ultrathin films (a few nanometers) relevant to OTFT devices, highly sensitive thin film characterization techniques, such as grazing incidence X-ray diffraction (GIXD) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy were used. The microstructure evolution during the thin film growth and under different process conditions was characterized. Theoretical models were used to calculate the precise molecular packing in organic thin films. We gained understanding of the impact of thin film microstructures on the charge mobility from different aspects. This study will provide feedbacks to new materials design to further improve their charge transport properties.

  16. Patterns and conformations in molecularly thin films

    NASA Astrophysics Data System (ADS)

    Basnet, Prem B.

    Molecularly thin films have been a subject of great interest for the last several years because of their large variety of industrial applications ranging from micro-electronics to bio-medicine. Additionally, molecularly thin films can be used as good models for biomembrane and other systems where surfaces are critical. Many different kinds of molecules can make stable films. My research has considered three such molecules: a polymerizable phospholipid, a bent-core molecules, and a polymer. One common theme of these three molecules is chirality. The phospolipid molecules studied here are strongly chiral, which can be due to intrinsically chiral centers on the molecules and also due to chiral conformations. We find that these molecules give rise to chiral patterns. Bent-core molecules are not intrinsically chiral, but individual molecules and groups of molecules can show chiral structures, which can be changed by surface interactions. One major, unconfirmed hypothesis for the polymer conformation at surface is that it forms helices, which would be chiral. Most experiments were carried out at the air/water interface, in what are called Langmuir films. Our major tools for studying these films are Brewster Angle Microscopy (BAM) coupled with the thermodynamic information that can be deduced from surface pressure isotherms. Phospholipids are one of the important constituents of liposomes -- a spherical vesicle com-posed of a bilayer membrane, typically composed of a phospholipid and cholesterol bilayer. The application of liposomes in drug delivery is well-known. Crumpling of vesicles of polymerizable phospholipids has been observed. With BAM, on Langmuir films of such phospholipids, we see novel spiral/target patterns during compression. We have found that both the patterns and the critical pressure at which they formed depend on temperature (below the transition to a i¬‘uid layer). Bent-core liquid crystals, sometimes knows as banana liquid crystals, have drawn increasing attention because of the richness in phases that they exhibit. Due to the unique coupling between dipole properties and the packing constraints placed by the bent shape, these molecules are emerging as strong candidates in electromechanical devices. However, most applications require that the molecules be aligned, which has proved difficult. Our group has tested such molecules both as Langmuir layers and, when transferred to a solid, as alignment layers with some limited success. However, these molecules do not behave well with the surfaces and the domains at the air/water interface tend to form ill-controlled multilayer structures since attraction with the surfaces is relatively weak. New bent-core molecules obtained from Prof. Dr. C. Tsehiemke from Department of Chemistry Institute of Organic Chemistry, Martin-Luther-University, Germany, have a hydrophilic group at one end. We expect this molecule to behave better on the surface because of the stronger attraction of the hydrophilic group towards the surface than for the bent-core molecules without the hydrophilic group. Polydimethylsiloxane (PDMS) is a polymer which finds many applications in modifying surface properties. It is used in manufacturing lubricants, protective coatings, hair conditioner and glass-coating. However its properties are not well understood. This polymer has been proposed to follow either helical or caterpillar conformations on a surface. The orientational order of CH3 side groups can test for these conformations (they would be predominantly up/down for the caterpillar conformation, but rotating through the entire 360 degree for the helical one). Thus previous work on the Langmuir polymer films at the air/water interface were complemented by deuterium NMR studies to probe their conformations at a surface. These experiments were performed using humid porous solids, in order to provide sufficient surface area for the technique. Previous tests in this group at room temperature were suggestive but inconclusive because of the rapid averaging motion of the molecules. Here, we attempt t

  17. thin films prepared by solid state reaction (induced by annealing) between the constituents in thin film form

    Microsoft Academic Search

    S. J. Li; J. C. Bernède; J. Pouzet; M. Jamali

    1996-01-01

    0953-8984\\/8\\/14\\/006\\/img2 thin films were obtained by solid state reaction (induced by annealing under S pressure) between the W and S constituents in thin film form. The tungsten layers were deposited by RF sputtering, while S layers were evaporated. The thickness of the layers varied between 50 and 100 nm. The films have been investigated using x-ray photoelectron spectroscopy, scanning electron

  18. Thin-film transistors based on p-type Cu2O thin films produced at room temperature

    Microsoft Academic Search

    Elvira Fortunato; Vitor Figueiredo; Pedro Barquinha; Elangovan Elamurugu; Raquel Barros; Gonçalo Gonçalves; Sang-Hee Ko Park; Chi-Sun Hwang; Rodrigo Martins

    2010-01-01

    Copper oxide (Cu2O) thin films were used to produce bottom gate p-type transparent thin-film transistors (TFTs). Cu2O was deposited by reactive rf magnetron sputtering at room temperature and the films exhibit a polycrystalline structure with a strongest orientation along (111) plane. The TFTs exhibit improved electrical performance such as a field-effect mobility of 3.9 cm2\\/V s and an on\\/off ratio

  19. Thin-film transistors based on p-type Cu2O thin films produced at room temperature

    NASA Astrophysics Data System (ADS)

    Fortunato, Elvira; Figueiredo, Vitor; Barquinha, Pedro; Elamurugu, Elangovan; Barros, Raquel; Gonçalves, Gonçalo; Park, Sang-Hee Ko; Hwang, Chi-Sun; Martins, Rodrigo

    2010-05-01

    Copper oxide (Cu2O) thin films were used to produce bottom gate p-type transparent thin-film transistors (TFTs). Cu2O was deposited by reactive rf magnetron sputtering at room temperature and the films exhibit a polycrystalline structure with a strongest orientation along (111) plane. The TFTs exhibit improved electrical performance such as a field-effect mobility of 3.9 cm2/V s and an on/off ratio of 2×102.

  20. Thin Film Femtosecond Laser Damage Competition

    SciTech Connect

    Stolz, C J; Ristau, D; Turowski, M; Blaschke, H

    2009-11-14

    In order to determine the current status of thin film laser resistance within the private, academic, and government sectors, a damage competition was started at the 2008 Boulder Damage Symposium. This damage competition allows a direct comparison of the current state of the art of high laser resistance coatings since they are tested using the same damage test setup and the same protocol. In 2009 a high reflector coating was selected at a wavelength of 786 nm at normal incidence at a pulse length of 180 femtoseconds. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials and layer count, and spectral results will also be shared.

  1. Glow discharge plasma deposition of thin films

    DOEpatents

    Weakliem, Herbert A. (Pennington, NJ); Vossen, Jr., John L. (Bridgewater, NJ)

    1984-05-29

    A glow discharge plasma reactor for deposition of thin films from a reactive RF glow discharge is provided with a screen positioned between the walls of the chamber and the cathode to confine the glow discharge region to within the region defined by the screen and the cathode. A substrate for receiving deposition material from a reactive gas is positioned outside the screened region. The screen is electrically connected to the system ground to thereby serve as the anode of the system. The energy of the reactive gas species is reduced as they diffuse through the screen to the substrate. Reactive gas is conducted directly into the glow discharge region through a centrally positioned distribution head to reduce contamination effects otherwise caused by secondary reaction products and impurities deposited on the reactor walls.

  2. Structure of Thin-Film Lithium Microbatteries

    NASA Technical Reports Server (NTRS)

    Whitacre, Jay F. (Inventor); Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor)

    2003-01-01

    A process for making thin-film batteries including the steps of cleaning a glass or silicon substrate having an amorphous oxide layer several microns thick; defining with a mask the layer shape when depositing cobalt as an adhesion layer and platinum as a current collector; using the same mask as the preceding step to sputter a layer of LiC(0)O2, on the structure while rocking it back and forth; heating the substrate to 300 C. for 30 minutes; sputtering with a new mask that defines the necessary electrolyte area; evaporating lithium metal anodes using an appropriate shadow mask; and, packaging the cell in a dry-room environment by applying a continuous bead of epoxy around the active cell areas and resting a glass slide over the top thereof. The batteries produced by the above process are disclosed.

  3. Transparent Conductive Oxides in Thin Film Photovoltaics

    NASA Astrophysics Data System (ADS)

    Hamelmann, Frank U.

    2014-11-01

    This paper show results from the development of transparent conductive oxides (TCO's) on large areas for the use as front electrode in thin film silicon solar modules. It is focused on two types of zinc oxide, which are cheap to produce and scalable to a substrate size up to 6 m2. Low pressure CVD with temperatures below 200°C can be used for the deposition of boron doped ZnO with a native surface texture for good light scattering, while sputtered aluminum doped ZnO needs a post deposition treatment in an acid bath for a rough surface. The paper presents optical and electrical characterization of large area samples, and also results about long term stability of the ZnO samples with respect to the so called TCO corrosion.

  4. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, R.A.; Chen, W.S.

    1985-06-11

    Disclosed is a thin film heterojunction solar cell, said heterojunction comprising a p-type I-III-IV[sub 2] chalcopyrite substrate and an overlying layer of an n-type ternary mixed metal compound wherein said ternary mixed metal compound is applied to said substrate by introducing the vapor of a first metal compound to a vessel containing said substrate from a first vapor source while simultaneously introducing a vapor of a second metal compound from a second vapor source of said vessel, said first and second metals comprising the metal components of said mixed metal compound; independently controlling the vaporization rate of said first and second vapor sources; reducing the mean free path between vapor particles in said vessel, said gas being present in an amount sufficient to induce homogeneity of said vapor mixture; and depositing said mixed metal compound on said substrate in the form of a uniform composition polycrystalline mixed metal compound. 5 figs.

  5. Stabilization of the dissipation-free current transport in inhomogeneous MgB2 thin films

    NASA Astrophysics Data System (ADS)

    Treiber, S.; Stahl, C.; Schütz, G.; Soltan, S.; Albrecht, J.

    2014-11-01

    In type-II superconductors at T = 0 the critical current density is determined by the pinning of flux lines. Considering an arbitrarily shaped energy landscape the pinning force at each pinning site is given by the derivative of the flux line energy with respect to the considered direction. At finite temperatures, in addition, thermal activation can lead to a depinning of flux lines. The governing property in this case is the depth of the corresponding pinning potential, i.e. the pinning energy. We show a detailed analysis of both pinning forces and pinning energies of MgB2 films with inhomogeneous microstructure. We show that a pronounced increase of the pinning energy is responsible for the significantly enhanced stability of the dissipation-free current transport in thin inhomogeneous MgB2 films. This is found even if the corresponding pinning forces are small.

  6. Stress induced deformations of thin silicon dioxide films

    NASA Astrophysics Data System (ADS)

    Serrano, Justin Raymond

    Residual compressive stresses are commonplace in semiconductor processing and are a leading cause of deformation and delamination of thin films. The principles of stress-induced mechanical deformation can be harnessed to produce controllable changes in the morphology of thin films. For this thesis work, deformations of thin silicon dioxide films which result from the compressive stress in the films have been investigated. Thermally grown SiO2 films were irradiated with a tightly focused laser pulse which locally melts the silicon substrate under the film. At low incident fluences, the compressive film over the molten substrate deforms over the irradiated area and results in an undulated morphology with large length-to-height aspect ratios. Increasing laser power leads to a transition in the film morphology and results in blister-like structures. The structures are the result of delamination of the film---due to the compressive stress in the films---from the substrate over the irradiation area. Because of delamination, the region under the blister was void, and had an encapsulated volume <1 mum3. Contrary to conventional laser processing of surfaces, both types of morphology had length scales which were directly related to film properties and exhibited little dependence on laser parameters. The behavior of compressive silicon dioxide films deposited by magnetron sputtering, on PMMA, a low Tg polymer, were also studied. SiO2 films exhibited a linear increase in the surface roughness for deposited thickness below ˜10 nm; larger thickness showed an almost unchanged roughness. Since stresses generated in thin films during sputtering are independent of surface morphology, the roughening of the films is treated as a stress-driven roughening mechanism, where the compressive stress in the films causes buckling of the films during growth.

  7. Superconductor films with improved flux pinning and reduced AC losses

    DOEpatents

    Goyal, Amit (Knoxville, TN)

    2011-04-05

    The present invention relates to a method for producing a defect-containing superconducting film, the method comprising (a) depositing a phase-separable layer epitaxially onto a biaxially-textured substrate, wherein the phase-separable layer includes at least two phase-separable components; (b) achieving nanoscale phase separation of the phase-separable layer such that a phase-separated layer including at least two phase-separated components is produced; and (c) depositing a superconducting film epitaxially onto said phase-separated components of the phase-separated layer such that nanoscale features of the phase-separated layer are propagated into the superconducting film.

  8. Magnetic Characteristics of Copper Ion-Modified DNA Thin Films

    NASA Astrophysics Data System (ADS)

    Dugasani, Sreekantha Reddy; Lee, Namhoon; Lee, Junwye; Kim, Byeonghoon; Hwang, Si Un; Lee, Keun Woo; Kang, Won Nam; Park, Sung Ha

    2013-05-01

    We developed a new method of fabricating a divalent copper ion (Cu2+) modified DNA thin film on a glass substrate and studied its magnetic properties. We evaluated the coercive field (Hc), remanent magnetization (Mr), susceptibility (?), and thermal variation of magnetization with varying Cu2+ concentrations [Cu2+] resulting in DNA thin films. Although thickness of the two dimensional DNA thin film with Cu2+ in dry state was extremely thin (0.6 nm), significant ferromagnetic signals were observed at room temperature. The DNA thin films with a [Cu2+] near 5 mM showed the distinct S-shape hysteresis with appreciable high Hc, Mr and ? at low field (<=600 Oe). These were primarily caused by the presence of small magnetic dipoles of Cu2+ coordination on the DNA molecule, through unpaired d electrons interacting with their nearest neighbors and the inter-exchange energy in the magnetic dipoles making other neighboring dipoles oriented in the same direction.

  9. Magnetic characteristics of copper ion-modified DNA thin films.

    PubMed

    Dugasani, Sreekantha Reddy; Lee, Namhoon; Lee, Junwye; Kim, Byeonghoon; Hwang, Si Un; Lee, Keun Woo; Kang, Won Nam; Park, Sung Ha

    2013-01-01

    We developed a new method of fabricating a divalent copper ion (Cu(2+)) modified DNA thin film on a glass substrate and studied its magnetic properties. We evaluated the coercive field (Hc), remanent magnetization (Mr), susceptibility (?), and thermal variation of magnetization with varying Cu(2+) concentrations [Cu(2+)] resulting in DNA thin films. Although thickness of the two dimensional DNA thin film with Cu(2+) in dry state was extremely thin (0.6?nm), significant ferromagnetic signals were observed at room temperature. The DNA thin films with a [Cu(2+)] near 5?mM showed the distinct S-shape hysteresis with appreciable high Hc, Mr and ? at low field (?600?Oe). These were primarily caused by the presence of small magnetic dipoles of Cu(2+) coordination on the DNA molecule, through unpaired d electrons interacting with their nearest neighbors and the inter-exchange energy in the magnetic dipoles making other neighboring dipoles oriented in the same direction. PMID:23660965

  10. Far Infrared Spectroscopy of Ultra-Thin Films.

    NASA Astrophysics Data System (ADS)

    da Costa, Victor M.

    1988-06-01

    This dissertation describes the development of a double polarization modulation technique, which allows for high far-infrared sensitivity to dielectric films deposited on metallized substrates. This new spectroscopy is based on the polarization specificity of the grazing angle reflectance of a thin dielectric coating on a conducting surface. The design is a modification of a Martin-Puplett configuration Michelson interferometer. The reflection absorption (RA) process has been computer modeled. Based on this model, far-infrared RA spectroscopy is compared to both mid-infrared RA spectroscopy and to standard normal transmission experiments. Physical arguments are presented to explain the differences between them in terms of macroscopic fields and the classical oscillator model of the dielectric function. The computer model allows for spectral line fitting and a method for fitting RA spectra is discussed. Far-infrared spectra and analysis are performed for two different thin film systems. The first system is a highly ionic thin film sample of potassium iodide (KI). Through fits to the KI thin film spectra, the effect of two phonon processes on the bulk LO mode of the KI crystal is discussed along with possible surface effects in the very thin samples. The second thin film system is the polymer Poly-Ethylene Oxide (PEO). The far-infrared spectra obtained from these polymer films is shown to be related to the high degree of crystallinity obtainable in the thin polymer film.

  11. The origin of haze in CVD tin oxide thin films

    NASA Astrophysics Data System (ADS)

    Szanyi, János

    2002-01-01

    The origin of haze was investigated in antimony-doped tin oxide thin films, and in double-stack thin films of fluorine-doped tin oxide/antimony-doped tin oxide, both deposited by chemical vapor deposition onto soda-lime-silica float glass substrates. These transparent conductive oxide thin films are of great importance in the production of solar control architectural glazing units. Therefore, understanding the origins of haze is necessary to the development of coated, IR-reflecting glass windows with low overall haze levels. Haze measurements of as-prepared and polished samples were correlated with surface roughness and concentration of internal hole defects. Surface roughnesses were evaluated by atomic force microscopy, and characterized by estimated RMS values. In thin tin oxide films (<2000 Å) internal hole defects caused haze, while in thick tin oxide films (>4000 Å) surface roughness was the primary source of haze.

  12. Corrosion pits in thin films of stainless steel

    SciTech Connect

    Ryan, M.P.; Isaacs, H.S. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science] [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Laycock, N.J. [Materials Performance Technologies, Lower Hutt (New Zealand)] [Materials Performance Technologies, Lower Hutt (New Zealand); Newman, R.C. [Univ. of Manchester (United Kingdom). Inst. of Science and Technology] [Univ. of Manchester (United Kingdom). Inst. of Science and Technology

    1999-01-01

    Thin stainless steel films were prepared by sputter deposition onto silicon substrates using a 304 stainless steel target. The film composition was essentially that of 304 stainless steel, but they had a body-centered cubic structure and were free of sulfide inclusions. Potentiodynamic polarization curves were obtained for thin films in various chloride-containing solutions and compared to results from conventional stainless steel samples. In addition, video images of two-dimensional pits in thin films were used to determine the anodic pit current density as functions of potential and chloride concentration. Thin stainless steel films were found to be significantly more resistant to pit initiation than their bulk counterparts, but pit propagation was possible at relatively low potentials. A diffusion-controlled growth regime was identified at high potentials, with a transition to mixed activation/ohmic control at lower potentials (just above that required for repassivation).

  13. Properties of Amorphous Carbon Thin Films for Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Mohamad, F.; Hanib, N. M.; Noor, U. M.; Rusop, M.

    2010-03-01

    This paper is presented the properties of amorphous carbon (a-C) thin films for solar cell application. Amorphous carbon thin films have been deposited on silicon substrate by thermal chemical vapor deposition (thermal-CVD) method at various deposition temperatures. The surface morphology, electrical properties and crystallinity of these films have been studied using Analytical Scanning Electron Microscope (SEM) JEOL JSM-6360LA, Current Voltage (I-V) Measurement (Advantest R6243 DC Voltage Current Source/Monitor Software) and the D5000 Siemen Difractrometer (XRD) respectively . It was found that increasing deposition temperature had the most influence on the a-C thin films properties. In addition the carrier gas flow also showed a secondary impact on the properties of a-C thin films.

  14. Synthesis and Characterization of Magnesium-Alloyed Hematite Thin Films

    NASA Astrophysics Data System (ADS)

    Tang, Houwen; Matin, M. A.; Wang, Heli; Al-Jassim, Mowafak; Turner, John; Yan, Yanfa

    2012-11-01

    We have synthesized pure and Mg-alloyed hematite thin films on F-doped, SnO2-coated glass substrates by radiofrequency magnetron cosputtering of iron oxide with and without MgO sources in mixed Ar/O2 and mixed N2/O2 ambient. We found that hematite films deposited in N2/O2 ambient exhibited much poorer crystallinity than those deposited in Ar/O2 ambient. We determined that Mg alloying led to increased crystallinity and bandgap. Furthermore, we found that Mg alloying inverted the type of conductivity of the thin films: pure hematite thin films exhibited n-type conductivity, whereas Mg-alloyed hematite thin films exhibited p-type conductivity.

  15. Method for making surfactant-templated thin films

    DOEpatents

    Brinker, C. Jeffrey (Albuquerque, NM); Lu, Yunfeng (New Orleans, LA); Fan, Hong You (Albuquerque, NM)

    2010-08-31

    An evaporation-induced self-assembly method to prepare a porous, surfactant-templated, thin film by mixing a silica sol, a solvent, a surfactant, and an interstitial compound, evaporating a portion of the solvent to form a liquid, crystalline thin film mesophase material, and then removal of the surfactant template. Coating onto a substrate produces a thin film with the interstitial compound either covalently bonded to the internal surfaces of the ordered or disordered mesostructure framework or physically entrapped within the ordered or disordered mesostructured framework. Particles can be formed by aerosol processing or spray drying rather than coating onto a substrate. The selection of the interstitial compound provides a means for developing thin films for applications including membranes, sensors, low dielectric constant films, photonic materials and optical hosts.

  16. Method for making surfactant-templated thin films

    DOEpatents

    Brinker, C. Jeffrey (Albuquerque, NM); Lu, Yunfeng (San Jose, CA); Fan, Hongyou (Albuquerque, NM)

    2002-01-01

    An evaporation-induced self-assembly method to prepare a porous, surfactant-templated, thin film by mixing a silica sol, a solvent, a surfactant, and an interstitial compound, evaporating a portion of the solvent to form a liquid, crystalline thin film mesophase material, and then removal of the surfactant template. Coating onto a substrate produces a thin film with the interstitial compound either covalently bonded to the internal surfaces of the ordered or disordered mesostructure framework or physically entrapped within the ordered or disordered mesostructured framework. Particles can be formed by aerosol processing or spray drying rather than coating onto a substrate. The selection of the interstitial compound provides a means for developing thin films for applications including membranes, sensors, low dielectric constant films, photonic materials and optical hosts.

  17. Suppression of copper thin film loss during graphene synthesis.

    PubMed

    Lee, Alvin L; Tao, Li; Akinwande, Deji

    2015-01-28

    Thin metal films can be used to catalyze the growth of nanomaterials in place of the bulk metal, while greatly reducing the amount of material used. A big drawback of copper thin films (0.5-1.5 ?m thick) is that, under high temperature/vacuum synthesis, the mass loss of films severely reduces the process time due to discontinuities in the metal film, thereby limiting the time scale for controlling metal grain and film growth. In this work, we have developed a facile method, namely "covered growth" to extend the time copper thin films can be exposed to high temperature/vacuum environment for graphene synthesis. The key to preventing severe mass loss of copper film during the high temperature chemical vapor deposition (CVD) process is to have a cover piece on top of the growth substrate. This new "covered growth" method enables the high-temperature annealing of the copper film upward of 4 h with minimal mass loss, while increasing copper film grain and graphene domain size. Graphene was then successfully grown on the capped copper film with subsequent transfer for device fabrication. Device characterization indicated equivalent physical, chemical, and electrical properties to conventional CVD graphene. Our "covered growth" provides a convenient and effective solution to the mass loss issue of thin films that serve as catalysts for a variety of 2D material syntheses. PMID:25552194

  18. X-ray diffraction characterization of thin superconductive films

    SciTech Connect

    Kozaczek, K.J.; Watkins, T.R. [Oak Ridge National Lab., TN (United States); Book, G.W.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering

    1995-12-31

    The physical and mechanical properties of thin films are often different from the properties of bulk material and are dictated by the film/substrate orientation relationship, crystal anisotropy and crystalgraphic texture of the film. X-ray diffraction texture analysis provides information about preferential film growth and can be used for optimization of deposition parameters and prediction of properties of thin films. An x-ray back reflection technique using the Braga-Brentano geometry with experimental corrections for absorption and defocusing was used to study thin ceramic films deposited by combustion chemical vapor deposition (CCVD). The film/substrate orientation relationships of YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) superconducting thin films deposited via CCVD on single crystal MgO and polycrystalline silver substrates were studied. The as-deposited films on single crystal (100) MgO substrates showed strong preferential growth with the basal plane parallel to the substrate surface (c-axis up growth). Texture analysis showed two in-plane alignment orientations of the film with respect to the substrate, with YBCO [100] and [110] aligned with the [100] MgO substrate. YBCO films deposited on cold-rolled polycrystalline silver displayed c-axis up growth indicating that the orientation of the polycrystalline substrate (brass type texture) did not induce detectable in-plane preferential growth of the YBCO.

  19. Carbon nanotube based nanostructured thin films: preparation and application

    NASA Astrophysics Data System (ADS)

    Fu, Li; Yu, Aimin

    2013-08-01

    Hybrid thin films of multi-walled carbon nanotube (MWCNT) and titania were fabricated on quartz slides by alternatively depositing MWCNT and titanium(IV) bis(ammonium lactato) dihydroxide (TALH) via a solution based layer-by-layer (LbL) self-assembly method followed by calcination to convert TALH to crystalline titania. The multilayer film build-up was monitored by UV-vis spectroscopy which indicated the linear growth of the film with the bilayer number. XRD confirmed the formation of anantase titania after heat treatment. The photocatalytic property of the hybrid thin film was evaluated by its capacity to degrade rhodamine B under the UV illumination. Compared with pure TiO2 film, experiments showed that the MWCNT/TiO2 hybrid film had a much higher photocatalytic activity under the same conditions. The first order rate constant of photocatalysis of 30 bilayers of hybrid film was approximately 8-fold higher than that of 30 bilayers of pure TiO2 film. In addition, the degradation efficiency of MWCNT/TiO2 hybrid thin film increased with its thickness while pure titania film remained unchanged. A 30 bilayers hybrid thin film that contains about 0.2 mg MWCNT/TiO2 catalyst was capable of completely degrading 10 mL of 2 mg/L Rh B solution within 5 hours. The results also indicated that the hybrid catalyst could be reused for several cycles.

  20. Integration of thin film decoupling capacitors

    SciTech Connect

    Garino, T.; Dimos, D.; Lockwood, S.

    1994-10-01

    Thin film decoupling capacitors consisting of submicron thick, sol-gel Pb(Zr,Ti)O{sub 3} layers between Pt electrodes on a Si substrate have recently been developed. Because the capacitor structure needs to be only {approximately}3 {mu}m thick, these devices offer advantages such as decreased package volume and ability to integrate so that interconnect inductance is decreased, which allows faster IC processing rates. To fully utilize these devices, techniques of integrating them onto packages such as multi-chip modules and printed wiring boards or onto IC dies must be developed. The results of our efforts at developing integration processes for these capacitors are described here. Specifically, we have demonstrated a process for printing solder on the devices at the Si wafer level and reflowing it to form bumps and have developed a process for fabricating the devices on thin (25 to 75 {mu}m) substrates to facilitate integration onto ICs and printed wiring boards. Finally, we assessed the feasibility of fabricating the devices on rough surfaces to determine whether it would be possible to fabricate these capacitors directly on multi-layer ceramic substrates.

  1. Thin film properties by facing targets sputtering system

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Hwan; Son, In Hwan; Song, Ki Bong; Kong, Sok Hyun; Keum, Min Jong; Nakagawa, Shigeki; Naoe, Masahiko

    2001-01-01

    In this study, film thickness distribution and c-axis crystalline orientation of deposited thin films were studied after preparing Co-Cr thin films, a promising ultra-high density perpendicular magnetic recording media, with a facing targets sputtering (FTS) apparatus. Electrical discharge characteristics needed for the optimum operation of sputter device was also studied in order to prepare thin films of superior c-axis crystalline orientation with FTS method (apparatus) in which thin film of fine quality can be formed because temperature increase of substrate due to the bombardment of high-energy particles can be restrained. As a result of the study, it is confirmed that the FTS method can give stable working under broad magnetic field and range of gas pressure and stable electrical discharge under low Ar gas pressure. Film thickness of prepared thin film shows fairy regular distribution and could obtain good thin films whose dispersion angle of c-axis crystalline orientation is about 3.5°.

  2. Nanoscale Thin Film Electrolytes for Clean Energy Applications

    SciTech Connect

    Nandasiri, Manjula I.; Sanghavi, Rahul P.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai

    2012-02-01

    Ceria and zirconia based systems can be used as electrolytes to develop solid oxide fuel cells for clean energy production and to prevent air pollution by developing efficient, reliable oxygen sensors. In this study, we have used oxygen plasma assisted molecular beam epitaxy (OPA-MBE) to grow samaria doped ceria (SDC), to understand the role of dopant concentration and geometry of the films towards the ionic conduction in these thin films. We have also discussed the Gd doped CeO2 (GDC) and Gd stabilized ZrO2 (GSZ) multi-layer thin films to investigate the effect of interfacial phenomena on the ionic conductivity of these hetero-structures. We found the optimum concentration to be 15 mol % SmO1.5, for achieving lowest electrical resistance in SDC thin films. The electrical resistance decreases with the increase in film thickness up to 200 nm. The results demonstrate the usefulness of this study towards establishing an optimum dopant concentration and choosing an appropriate thin film thickness to ameliorate the conductance of the SDC material system. Furthermore, we have explored the conductivity of highly oriented GDC and GSZ multi-layer thin films, wherein the conductivity increased with an increase in the number of layers. The extended defects and lattice strain near the interfaces increase the density of oxygen vacancies, which leads to enhanced ionic conductivity in multi-layer thin films.

  3. Multi-modal sensing using photoactive thin films

    NASA Astrophysics Data System (ADS)

    Ryu, Donghyeon; Loh, Kenneth J.

    2014-08-01

    The need for a reliable prognosis of the health of structural systems has promoted the development of sensing technologies capable of simultaneously detecting multiple types of damage. However, conventional sensors are designed to only measure a specific structural response (e.g., strain, displacement, or acceleration). This limitation forces one to use a wide variety of sensors densely instrumented on a given structure, which results in high overhead costs and requires extensive signal processing of raw sensor data. In this study, a photoactive thin film that has been engineered for multi-modal sensing to selectively detect strain and pH is proposed. In addition, the thin film is self-sensing in that it does not require external power to operate. Instead, light illumination causes the photoactive film to generate an electrical current, whose magnitude is directly related to applied strains (for deformations, impact or cracks) or pH (as a precursor of corrosion). First, the thin films were fabricated by spin-coating photoactive and conjugated polymers like poly(3-hexylthiophene) (P3HT). The thin film was also encoded with pH sensitivity by integrating polyaniline (PANI) as one component within the multilayered film architecture. Second, the optical response of the P3HT and PANI thin films subjected to applied strains or pH was characterized using absorption spectroscopy. Lastly, it was also verified that the thin films could selectively sense strain or pH depending on the wavelengths of light used for sensor interrogation.

  4. Nanomechanical behavior of (1 0 0) oriented titanium thin films

    NASA Astrophysics Data System (ADS)

    Vasu, Kuraganti; Ghanashyam Krishna, Mamidipudi; Padmanabhan, Kuppuswamy Anantha

    2014-03-01

    Titanium thin films were deposited on single crystal Si (3 1 1) and polycrystalline 316 LN nuclear grade stainless steel substrates by RF magnetron sputtering. X-ray diffraction revealed that, irrespective of substrate type, films exhibit preferential growth along the (1 0 0) plane. The microstructure of the films corresponds to the zone-I type in structure zone model on both substrates. The hardness and Young's modulus of the films were extracted from load-displacement curves. The maximum values of hardness and Young's modulus were 12 and 132 GPa respectively for 220 nm thin film on SS substrate. The electrical resistivity data revealed that the films are metallic in nature and the resistivity is lower in the case of the 220 nm thickness film, on both substrates. The observed changes in mechanical and electrical properties can be correlated with variations in the microstructure of Ti films.

  5. Hafnia: Energetics of Thin Films and Nanoparticles

    SciTech Connect

    Zhou, W.; Ushakov, S; Wang, T; Ekerdt, J; Demkov, A; Navrotsky, A

    2010-01-01

    Crystallization energetics of amorphous hafnia powders and thin films on platinum substrates was studied by differential scanning calorimetry and time-resolved high temperature x-ray diffraction. For initially amorphous 25 and 20 nm films from atomic layer deposition, crystallization enthalpy decreases from -38 to -32 kJ/mol, and crystallization temperature increases from 388 to 417 C as thickness decreases. Enthalpy of water vapor adsorption on the surface of monoclinic hafnia was measured for both bulk powder and nanoparticles and was found to vary from -110 to -130 kJ/mol for coverage of -5 H{sub 2}O/nm{sup 2}. The enthalpies of monoclinic hafnia with various surface areas, prepared by crystallization and annealing of an amorphous hafnia precursor, were measured by high temperature oxide melt solution calorimetry. Under the previously used assumption that the interfacial enthalpy is 20% of the surface enthalpy, the surface enthalpy was calculated from experimental data as 2.8 {+-} 0.1 J/m{sup 2} for the hydrated surface and 3.7 {+-} 0.1 J/m{sup 2} for the anhydrous hafnia surface. These values are similar to those measured previously for monoclinic zirconia.

  6. Josephson junction in a thin film

    SciTech Connect

    Kogan, V. G.; Dobrovitski, V. V.; Clem, J. R.; Mawatari, Yasunori; Mints, R. G.

    2001-04-01

    The phase difference {phi}(y) for a vortex at a line Josephson junction in a thin film attenuates at large distances as a power law, unlike the case of a bulk junction where it approaches exponentially the constant values at infinities. The field of a Josephson vortex is a superposition of fields of standard Pearl vortices distributed along the junction with the line density {phi}'(y)/2{pi}. We study the integral equation for {phi}(y) and show that the phase is sensitive to the ratio l/{Lambda}, where l={lambda}{sub J}{sup 2}/{lambda}{sub L}, {Lambda}=2{lambda}{sub L}{sup 2}/d, {lambda}{sub L}, and {lambda}{sub J} are the London and Josephson penetration depths, and d is the film thickness. For l<<{Lambda}, the vortex ''core'' of the size l is nearly temperature independent, while the phase ''tail'' scales as l{Lambda}/y{sup 2}={lambda}{sub J}2{lambda}{sub L}/d/y{sup 2}; i.e., it diverges as T{yields}T{sub c}. For l>>{Lambda}, both the core and the tail have nearly the same characteristic length l{Lambda}.

  7. Photoinduced conductivity in tin dioxide thin films

    SciTech Connect

    Muraoka, Y.; Takubo, N.; Hiroi, Z. [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

    2009-05-15

    The effects of ultraviolet light irradiation on the conducting properties of SnO{sub 2-x} thin films grown epitaxially on TiO{sub 2} or Al{sub 2}O{sub 3} single-crystal substrates are studied at room temperature. A large increase in conductivity by two to four orders of magnitude is observed with light irradiation in an inert atmosphere and remains after the light is removed. The high-conducting state reverts to the original low-conducting state by exposing it to oxygen gas. These reversible phenomena are ascribed to the desorption and adsorption of negatively charged oxygen species at the grain boundaries, which critically change the mobility of electron carriers already present inside grains by changing the potential barrier height at the grain boundary. The UV light irradiation provides us with an easy and useful route to achieve a high-conducting state even at low carrier density in transparent conducting oxides and also to draw an invisible conducting wire or a specific pattern on an insulating film.

  8. Transparent conducting thin films for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Malave-Sanabria, Tania; Hambourger, Paul; Rutledge, Sharon K.; Roig, David; Degroh, Kim K.; Hung, Ching-Cheh

    1994-01-01

    Transparent conductive thin films are required for a variety of optoelectronic applications: automotive and aircraft windows, and solar cells for space applications. Transparent conductive coatings of indium-tin-oxide (ITO)-magnesium fluoride (MgF2) and aluminum doped zinc oxide (AZO) at several dopant levels are investigated for electrical resistivity (sheet resistance), carrier concentration, optical properties, and atomic oxygen durability. The sheet resistance values of ITO-MgF2 range from 10(exp 2) to 10(exp 11) ohms/square, with transmittance of 75 to 86 percent. The AZO films sheet resistances range from 10(exp 7) to 10(exp 11) ohms/square with transmittances from 84 to 91 percent. It was found that in general, with respect to the optical properties, the zinc oxide (ZnO), AZO, and the high MgF2 content ITO-MgF2 samples, were all durable to atomic oxygen plasma, while the low MgF2 content of ITO-MgF2 samples were not durable to atomic oxygen plasma exposure.

  9. Optical absorption in tin selenide thin films

    NASA Astrophysics Data System (ADS)

    Wahab, Y. B.; Hutagalung, S. D.; Sakrani, S. B.

    1998-02-01

    Tin selenide (SnSe) thin films have been prepared by encapsulated selenization technique. The Sn/Se stacked films were deposited by vacuum evaporation and annealed at 200 degrees Celsius for 3 hours to form a stoichiometric SnSe compound. Optical absorption measurements were made on the as- prepared sample using spectrophotometer in the range from UV to visible region (200 - 900 nm). The absorption coefficient, (alpha) was found to be greater than 105 cm-1 that suggested the occurrence of either indirect allowed or direct forbidden optical transition. A further investigations on the (ahv)1/2 and (ahv)2/3 plots against photon energy have been carried out and the resulting optical bandgap obtained from indirect allowed transitions were 0.95 eV for 40.5 nm sample and reduced to 0.79 eV for 125 nm sample thickness. In the case of direct forbidden transition, the energy gaps were between 1.20 - 1.08 nm. The results also showed that the band gap decreased with increasing sample thickness.

  10. Bi 3 + cluster primary ions in SIMS depth profiling of YBaCuO high-temperature superconductor films

    Microsoft Academic Search

    M. N. Drozdov; Yu. N. Drozdov; D. V. Masterov; S. A. Pavlov; A. E. Parafin; G. L. Pakhomov

    2010-01-01

    SIMS depth profiling of YBa2Cu3O7 high-temperature superconductor films was performed using a TOF.SIMS-5 instrument. A new approach was proposed to obtain\\u000a additional information on the phase composition of YBa2Cu3O7 films based on detection of cluster secondary ions.

  11. Germanium Lift-Off Masks for Thin Metal Film Patterning

    NASA Technical Reports Server (NTRS)

    Brown, Ari

    2012-01-01

    A technique has been developed for patterning thin metallic films that are, in turn, used to fabricate microelectronics circuitry and thin-film sensors. The technique uses germanium thin films as lift-off masks. This requires development of a technique to strip or undercut the germanium chemically without affecting the deposited metal. Unlike in the case of conventional polymeric lift-off masks, the substrate can be exposed to very high temperatures during processing (sputter deposition). The reason why polymeric liftoff masks cannot be exposed to very high temperatures (greater than 100 C) is because (a) they can become cross linked, making lift-off very difficult if not impossible, and (b) they can outgas nitrogen and oxygen, which then can react with the metal being deposited. Consequently, this innovation is expected to find use in the fabrication of transition edge sensors and microwave kinetic inductance detectors, which use thin superconducting films deposited at high temperature as their sensing elements. Transition edge sensors, microwave kinetic inductance detectors, and their circuitry are comprised of superconducting thin films, for example Nb and TiN. Reactive ion etching can be used to pattern these films; however, reactive ion etching also damages the underlying substrate, which is unwanted in many instances. Polymeric lift-off techniques permit thin-film patterning without any substrate damage, but they are difficult to remove and the polymer can outgas during thin-film deposition. The outgassed material can then react with the film with the consequence of altered and non-reproducible materials properties, which, in turn, is deleterious for sensors and their circuitry. The purpose of this innovation was to fabricate a germanium lift-off mask to be used for patterning thin metal films.

  12. Stress Relaxation in Cu Thin Films

    NASA Astrophysics Data System (ADS)

    Witt, C.; Rosenberg, R.; Bonilla, G.; Shaw, T.

    2009-06-01

    Contributions from various deformation mechanisms to relax stresses in Cu thin films are of technological interest for interconnect reliability. Stress-induced voiding in Cu interconnects for example is one effective process to relax thermally induced stresses which occur during processing and testing at elevated temperatures. Voiding can result in considerable resistance changes in integrated circuits and is hence a reliability concern (1, 2). Concurrent to voiding, stresses can be relaxed by diffusional mass transport as previously reported (3), with the Cu/cap interface of particular importance. The use of CoWP capping layers instead of SiCN was shown to be effective in reducing both, stress relaxation rates (3) and electromigration failure rates (5). Depending on temperature, other deformation mechanisms may supplement the diffusion process or even dominate the relaxation rate. In this paper, we examined stress relaxation in Cu films with a Cu/CVD SiCN cap interface over a temperature range between 100°-300° C. Additionally, SEM based in-situ observations of voids were made. Experimentally, electroplated Cu films were used. During temperature cycling, the specimens were first heated to peak temperatures between 200°-400° C for 1 hr, followed by cooling to the relaxation temperature. The effects of cooling rate, peak temperature, and specimen history need to be considered to assess the interfacial mass transport kinetics. With respect to the temperature dependence the use of a single activation energy is found to be inadequate, suggesting a mechanism change at approximately 150° C. Provided that stress-induced voiding was minimized, at higher temperatures an activation energy of 0.9 eV was found, consistent with interface diffusion coupled with grain boundary diffusion..

  13. Investigation of heteroepitaxial growth of magnetite thin films

    Microsoft Academic Search

    G. E. Sterbinsky; J. Cheng; P. T. Chiu; B. W. Wessels; D. J. Keavney

    2007-01-01

    Epitaxial magnetite (FeO) thin films were deposited by molecular beam epitaxy using molecular oxygen as the oxidant. Films deposited on (001) SrTiO, (001) MgO, and (001) BaTiO surfaces are epitaxial with the film (001) parallel to the substrate (001) and the film <100> parallel to the substrate <100>. X-ray magnetic circular dichroism was used to determine the relative Fe{sup 2+}\\/Fe{sup

  14. Structural and optical properties of CdS thin films

    Microsoft Academic Search

    K. Senthil; D. Mangalaraj; Sa. K. Narayandass

    2001-01-01

    CdS thin films are deposited onto glass substrates by vacuum evaporation at 373K and the films are annealed at different temperatures. Rutherford backscattering spectrometry (RBS) and X-ray diffraction techniques are used to determine the thickness, composition, crystalline structure and grain size of the films. The films show a predominant hexagonal phase with small crystallites. The optical band gap of the

  15. Lithium cobalt oxide thin film and its electrochromism

    Microsoft Academic Search

    Guang Wei; Terry E. Haas; Ronald B. Goldner

    1989-01-01

    Thin films of lithium cobalt oxide have been prepared by RF-sputtering from powdered LiCoO2. These films permit reversible electrolytic removal of lithium ions upon application of an anodic voltage in a propylene carbonate-lithium perchlorate electrolyte, the films changing in color from a pale amber transparent state to a dark brown. A polycrystalline columnar film structure was revealed with SEM and

  16. Fabrication and characterization of nanocrystalline cobalt oxide thin films

    Microsoft Academic Search

    Biljana Pejova; Ardijana Isahi; Metodija Najdoski; Ivan Grozdanov

    2001-01-01

    A simple solution growth route has been employed to synthesize nanocrystalline cobalt oxide thin films on glass substrates. The obtained films were characterized by X-ray diffraction and FTIR spectroscopy. The as-deposited films were identified as a mixture of different phases of Co(OH)2, while the annealed ones as Co3O4. The absorption of the annealed films gradually decreases with an increase of

  17. Residual stress in spin-cast polyurethane thin films

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Zhang, Li

    2015-01-01

    Residual stress is inevitable during spin-casting. Herein, we report a straightforward method to evaluate the residual stress in as-cast polyurethane thin films using area shrinkage measurement of films in floating state, which shows that the residual stress is independent of radial location on the substrate and decreased with decreasing film thickness below a critical value. We demonstrate that the residual stress is developed due to the solvent evaporation after vitrification during spin-casting and the polymer chains in thin films may undergo vitrification at an increased concentration. The buildup of residual stress in spin-cast polymer films provides an insight into the size effects on the nature of polymer thin films.

  18. Growth of high Tc superconducting thin films for microwave applications

    SciTech Connect

    Wu, X.D.; Foltyn, S.R.; Muenchausen, R.E.; Dye, R.C.; Cooke, D.W.; Rollett, A.D.; Garcia, A.R.; Nogar, N.S. (Los Alamos National Lab., NM (USA)); Pique, A.; Edwards, R. (Neocera, New Brunswick, NJ (USA))

    1991-01-01

    High-{Tc} superconducting thin films of YBa{sub 2}Cu{sub 3}O{sub 7 {minus}{delta}} (YBCO) were deposited on sapphire substrates with buffer layers of yttria-stabilized zirconia and cerium oxide by using pulsed laser deposition (PLD) technique. The epitaxial relationship between the substrate and buffer layers as well as the buffer layer and the superconducting film was established. Furthermore, using the same thin film technique, YBCO superconducting thin films were deposited on both sides of substrates of up to 5 cm in diameter. The superconducting properties of the films on both the sapphire with buffer layers and large-area substrates were comparable to the ones of the best YBCO films. 8 refs., 6 figs.

  19. Polydimethylsiloxane thin film characterization using all-optical photoacoustic mechanism.

    PubMed

    Zou, Xiaotian; Wu, Nan; Tian, Ye; Zhang, Yang; Wang, Xingwei

    2013-09-01

    This paper presents a nondestructive ultrasound testing method for characterization of the resonant frequencies of polydimethylsiloxane (PDMS) thin film by using a miniature fiber optic photoacoustic (PA) probe. The PA probe was fabricated with an optical fiber and a synthesized gold nanocomposite. During the experiment, a cured PDMS thin film with a thickness of 220 ?m was immersed into a water medium using a custom-designed holder to clamp the film. An acoustic pulse was generated by the PA probe and propagated through the water media to excite the fixed film. A fiber optic pressure sensor based on the Fabry-Perot principle was used to collect the excited acoustic signals on the other side of the film. The acquired response of the acoustic pulse was used to compute the resonant frequencies of the PDMS thin film based on a deconvolution method. PMID:24085082

  20. Sensitive 3-omega measurements on epitaxial thermoelectric thin films

    NASA Astrophysics Data System (ADS)

    Liu, Y. Q.; Tainoff, D.; Boukhari, M.; Richard, J.; Barski, A.; Bayle-Guillemaud, P.; Hadji, E.; Bourgeois, O.

    2014-11-01

    Here we present a work on the development of a sensitive 3-omega instrumentation adapted for the measurement of the thermal conductivity of epitaxial thin films. The experimental setup has been validated by the measurements on an epitaxial germanium nanostructured thin film. This manganese doped germanium matrix contains Ge3Mn5 nanoinclusions having a diameter of 5 to 50 nm, grown by Molecular Beam Epitaxy (MBE). The 3 omega measurements have revealed that the thermal conductivity of GeMn nanostructured thin films can be decreased by a factor of ten as compared to the bulk value.

  1. Local deposition and patterning of catalytic thin films in microsystems

    NASA Astrophysics Data System (ADS)

    Vereshchagina, E.; Bliznyuk, O.; Tiggelaar, R. M.; Altena-Schildkamp, K.; Gardeniers, J. G. E.

    2012-04-01

    The local deposition of catalysts is desired in a wide range of catalytic microsystems (microreactors and sensors). In this study, we investigate technologies enabling deposition and patterning of catalyst thin films in a manner compatible with standard micromachining processes. We evaluate and compare deposition techniques based on a combination of a self-assembly, soft-lithography and conventional micromachining. Platinum (Pt) and palladium (Pd) were used as model catalysts, both as a sputtered thin film and as nanoparticles supported on ?-alumina. The thin films were characterized and tested in terms of their catalytic activity based on CO chemisorption measurements, stability and reproducibility.

  2. Electrospray aerosol deposition of water soluble polymer thin films

    NASA Astrophysics Data System (ADS)

    Sweet, Marshall L.; Pestov, Dmitry; Tepper, Gary C.; McLeskey, James T.

    2014-01-01

    We report the fabrication and characterization of thin films from the water soluble polymer sodium poly[2-(3-thienyl)-ethyloxy-4-butylsulfonate] (PTEBS) by electrospray deposition (ESD). Contiguous thin films were created by adjusting the parameters of the electrospray apparatus and solution properties to maintain a steady Taylor cone for uniform nanoparticle aerosolization and controlling the particle water content to enable coalescence with previously deposited particles. The majority of deposited particles had diameters less than 52 nm. A thin film of 64.7 nm with a root mean square surface roughness of 20.2 nm was achieved after 40 min of ESD.

  3. Thermoelastic response of thin metal films and their adjacent materials

    SciTech Connect

    Kang, S.; Yoon, Y.; Kim, J.; Kim, W. [Samsung Electronics Co., Yongin-Si, 446-712 Gyeonggi-do (Korea, Republic of)] [Samsung Electronics Co., Yongin-Si, 446-712 Gyeonggi-do (Korea, Republic of)

    2013-01-14

    A pulsed laser beam applied to a thin metal film is capable of launching an acoustic wave due to thermal expansion. Heat transfer from the thin metal film to adjacent materials can also induce thermal expansion; thus, the properties of these adjacent materials (as well as the thin metal film) should be considered for a complete description of the thermoelastic response. Here, we show that adjacent materials with a small specific heat and large thermal expansion coefficient can generate an enhanced acoustic wave and we demonstrate a three-fold increase in the peak pressure of the generated acoustic wave on substitution of parylene for polydimethylsiloxane.

  4. Thermoelastic response of thin metal films and their adjacent materials

    NASA Astrophysics Data System (ADS)

    Kang, S.; Yoon, Y.; Kim, J.; Kim, W.

    2013-01-01

    A pulsed laser beam applied to a thin metal film is capable of launching an acoustic wave due to thermal expansion. Heat transfer from the thin metal film to adjacent materials can also induce thermal expansion; thus, the properties of these adjacent materials (as well as the thin metal film) should be considered for a complete description of the thermoelastic response. Here, we show that adjacent materials with a small specific heat and large thermal expansion coefficient can generate an enhanced acoustic wave and we demonstrate a three-fold increase in the peak pressure of the generated acoustic wave on substitution of parylene for polydimethylsiloxane.

  5. Preparation and superconductivity of iron selenide thin films

    Microsoft Academic Search

    Y. Han; W. Y. Li; L. X. Cao; S. Zhang; B. Xu; B. R. Zhao

    2009-01-01

    FeSex (x = 0.80,0.84,0.88,0.92) thin films were prepared on SrTiO3(001)(STO), (La,Sr)(Al,Ta)O3(001) (LSAT), and LaAlO3(001) (LAO) substrates by a pulsed laser deposition method. All of the thin films show single-phase and c-axis oriented epitaxial growth, and are superconducting. Among them, the FeSe0.88 thin films show a Tc,onset of 11.8 K and a Tc,0 of 3.4 K. The upper critical magnetic field

  6. Relaxation of ferroelectric thin films of diisopropylammonium perchlorate.

    PubMed

    Zhu, Jiansheng; Gao, Kaige; Xiao, Shuyu; Qiu, Xiangbiao; Cai, Hong-Ling; Wu, X S

    2015-02-14

    Molecular ferroelectric thin films are highly desirable for their easy and environmentally friendly processing, light weight, and mechanical flexibility. A thin film of diisopropylammonium perchlorate (DIPAP) processed by a spin-coating method shows a good roughness and textured structure with (101) orientation in the ferroelectric phase with a space group of P1. Simultaneously, the thin film shows ferroelectricity and ferroelectric relaxivity above room temperature, which is completely different from crystals. These properties make DIPAP a candidate in sensing, data storage, electro-optics, and molecular/flexible electronics. PMID:25583685

  7. Development of Thin Film Ceramic Thermocouples for High Temperature Environments

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2004-01-01

    The maximum use temperature of noble metal thin film thermocouples of 1100 C (2000 F) may not be adequate for use on components in the increasingly harsh conditions of advanced aircraft and next generation launch technology. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically found in the form of rods or probes. NASA Glenn Research Center is investigating the feasibility of ceramics as thin film thermocouples for extremely high temperature applications to take advantage of the stability and robustness of ceramics and the non-intrusiveness of thin films. This paper will discuss the current state of development in this effort.

  8. DISSERTATION DEVICE PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS

    E-print Network

    Sites, James R.

    DISSERTATION DEVICE PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS Submitted by Markus Gloeckler PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS BE ACCEPTED AS FULFILLING IN PART REQUIREMENTS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS Thin-film solar cells have the potential to be an important

  9. Electrical & optical properties of nanocomposite MEH-PPV\\/ZnO thin film

    Microsoft Academic Search

    S. S. Shariffudin; M. H. Mamat; M. Rusop; N. S. Jumali; Z. Shaameri; A. S. Hamzah

    2010-01-01

    Nanocomposite thin films consist of conjugated polymer; MEH-PPV and inorganic material; ZnO were deposited using low cost spin coating method. The thin films characteristics were investigated in term of their electrical and optical properties; as each of it were heated at different temperature. The electrical properties of the thin films were studied to identify whether the nanocomposite thin films have

  10. New measurement capability measures semiconductor minority-carrier lifetimes in conditions that simulate thin-film

    E-print Network

    that simulate thin-film photovoltaic manufacturing environments. National Renewable Energy Laboratory (NREL of conditions in a thin-film photovoltaic (PV) manufacturing line. NREL's work in recent years has demonstrated a clear correlation between minority-carrier lifetime and thin-film PV device performance. Hence, the thin-film

  11. Film and membrane-model thermodynamics of free thin liquid films.

    PubMed

    Radke, C J

    2015-07-01

    In spite of over 7 decades of effort, the thermodynamics of thin free liquid films (as in emulsions and foams) lacks clarity. Following a brief review of the meaning and measurement of thin-film forces (i.e., conjoining/disjoining pressures), we offer a consistent analysis of thin-film thermodynamics. By carefully defining film reversible work, two distinct thermodynamic formalisms emerge: a film model with two zero-volume membranes each of film tension ?(f) and a membrane model with a single zero-volume membrane of membrane tension 2?(m). In both models, detailed thermodynamic analysis gives rise to thin-film Gibbs adsorption equations that allow calculation of film and membrane tensions from measurements of disjoining-pressure isotherms. A modified Young-Laplace equation arises in the film model to calculate film-thickness profiles from the film center to the surrounding bulk meniscus. No corresponding relation exists in the membrane model. Illustrative calculations of disjoining-pressure isotherms for water are presented using square-gradient theory. We report considerable deviations from Hamaker theory for films less than about 3nm in thickness. Such thin films are considerably more attractive than in classical Hamaker theory. Available molecular simulations reinforce this finding. PMID:25648681

  12. Thin Semiconductor/Metal Films For Infrared Devices

    NASA Technical Reports Server (NTRS)

    Lamb, James L.; Nagendra, Channamallappa L.

    1995-01-01

    Spectral responses of absorbers and reflectors tailored. Thin cermet films composites of metals and semiconductors undergoing development for use as broadband infrared reflectors and absorbers. Development extends concepts of semiconductor and dielectric films used as interference filters for infrared light and visible light. Composite films offer advantages over semiconductor films. Addition of metal particles contributes additional thermal conductivity, reducing thermal gradients and associated thermal stresses, with resultant enhancements of thermal stability. Because values of n in composite films made large, same optical effects achieved with lesser thicknesses. By decreasing thicknesses of films, one not only decreases weights but also contributes further to reductions of thermal stresses.

  13. Thin-Film Photovoltaic Solar Array Parametric Assessment

    NASA Technical Reports Server (NTRS)

    Hoffman, David J.; Kerslake, Thomas W.; Hepp, Aloysius F.; Jacobs, Mark K.; Ponnusamy, Deva

    2000-01-01

    This paper summarizes a study that had the objective to develop a model and parametrically determine the circumstances for which lightweight thin-film photovoltaic solar arrays would be more beneficial, in terms of mass and cost, than arrays using high-efficiency crystalline solar cells. Previous studies considering arrays with near-term thin-film technology for Earth orbiting applications are briefly reviewed. The present study uses a parametric approach that evaluated the performance of lightweight thin-film arrays with cell efficiencies ranging from 5 to 20 percent. The model developed for this study is described in some detail. Similar mass and cost trends for each array option were found across eight missions of various power levels in locations ranging from Venus to Jupiter. The results for one specific mission, a main belt asteroid tour, indicate that only moderate thin-film cell efficiency (approx. 12 percent) is necessary to match the mass of arrays using crystalline cells with much greater efficiency (35 percent multi-junction GaAs based and 20 percent thin-silicon). Regarding cost, a 12 percent efficient thin-film array is projected to cost about half is much as a 4-junction GaAs array. While efficiency improvements beyond 12 percent did not significantly further improve the mass and cost benefits for thin-film arrays, higher efficiency will be needed to mitigate the spacecraft-level impacts associated with large deployed array areas. A low-temperature approach to depositing thin-film cells on lightweight, flexible plastic substrates is briefly described. The paper concludes with the observation that with the characteristics assumed for this study, ultra-lightweight arrays using efficient, thin-film cells on flexible substrates may become a leading alternative for a wide variety of space missions.

  14. Investigation of TiO{sub x} barriers for their use in hybrid Josephson and tunneling junctions based on pnictide thin films

    SciTech Connect

    Döring, S., E-mail: sebastian.doering.1@uni-jena.de; Monecke, M.; Schmidt, S.; Schmidl, F.; Tympel, V.; Seidel, P., E-mail: paul.seidel@uni-jena.de [Institute of Solid State Physics, Friedrich-Schiller-Universität Jena, Helmholtzweg 5, 07743 Jena (Germany); Engelmann, J.; Kurth, F.; Iida, K.; Holzapfel, B. [Institute for Metallic Materials, IFW Dresden, Helmholtzstrasse 20, 01171 Dresden (Germany); Haindl, S. [Institute for Solid State Research, IFW Dresden, Helmholtzstrasse 20, 01171 Dresden (Germany); Mönch, I. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, 01171 Dresden (Germany)

    2014-02-28

    We tested oxidized titanium layers as barriers for hybrid Josephson junctions with high I{sub c}R{sub n}-products and for the preparation of junctions for tunneling spectroscopy. For that we firstly prepared junctions with conventional superconductor electrodes, such as lead and niobium, respectively. By tuning the barrier thickness, we were able to change the junction's behavior from a Josephson junction to tunnel-like behavior applicable for quasi-particle spectroscopy. Subsequently, we transferred the technology to junctions using Co-doped BaFe{sub 2}As{sub 2} thin films prepared by pulsed laser deposition as base electrode and evaporated Pb as counter electrode. For barriers with a thickness of 1.5?nm, we observe clear Josephson effects with I{sub c}R{sub n}?90??V at 4.2?K. These junctions behave SNS'-like (SNS: superconductor-normal conductor-superconductor) and are dominated by Andreev reflection transport mechanism. For junctions with barrier thickness of 2.0?nm and higher, no Josephson but SIS'- (SIS: superconductor-insulator-superconductor) or SINS'-like (SINS: superconductor-normal conductor-insulator-superconductor) behavior with a tunnel-like conductance spectrum was observed.

  15. Analytical and numerical modeling of surface morphologies in thin films

    SciTech Connect

    Genin, F.Y.

    1995-05-01

    Experimental studies have show that strains due to thermal expansion mismatch between a film and its substrate can produce very large stresses in the film that can lead to the formation of holes and hillocks. Based on a phenomenological description of the evolution of a solid surface under both capillary and stress driving forces and for surface and grain boundary self-diffusion, this article provides analytical and numerical solutions for surface profiles of model geometries in polycrystalline thin films. Results can explain a variety of surface morphologies commonly observed experimentally and are discussed to give some practical insights on how to control the growth of holes and hillocks in thin films.

  16. Profile measurements of thin liquid films using reflectometry

    NASA Astrophysics Data System (ADS)

    Hanchak, M. S.; Vangsness, M. D.; Byrd, L. W.; Ervin, J. S.; Jones, J. G.

    2013-11-01

    Microscope-based reflectometry was used to measure the thickness profile of thin films of n-octane on silicon wafer substrates. Coupled with micro-positioning motorized stages and custom software, two-dimensional profiles of the film thickness from the adsorbed film (˜10 nm) to the intrinsic meniscus (˜1000 nm) were automatically and repeatedly measured. The reflectometer aperture was modified to provide better spatial resolution in areas of high curvature, the transition region, where evaporative flux is at a maximum. This technique will provide data for the validation of both existing and future models of thin film evaporation.

  17. Glass transition dynamics of stacked thin polymer films

    NASA Astrophysics Data System (ADS)

    Fukao, Koji; Terasawa, Takehide; Oda, Yuto; Nakamura, Kenji; Tahara, Daisuke

    2011-10-01

    The glass transition dynamics of stacked thin films of polystyrene and poly(2-chlorostyrene) were investigated using differential scanning calorimetry and dielectric relaxation spectroscopy. The glass transition temperature Tg of as-stacked thin polystyrene films has a strong depression from that of the bulk samples. However, after annealing at high temperatures above Tg, the stacked thin films exhibit glass transition at a temperature almost equal to the Tg of the bulk system. The ?-process dynamics of stacked thin films of poly(2-chlorostyrene) show a time evolution from single-thin-film-like dynamics to bulk-like dynamics during the isothermal annealing process. The relaxation rate of the ? process becomes smaller with increase in the annealing time. The time scale for the evolution of the ? dynamics during the annealing process is very long compared with that for the reptation dynamics. At the same time, the temperature dependence of the relaxation time for the ? process changes from Arrhenius-like to Vogel-Fulcher-Tammann dependence with increase of the annealing time. The fragility index increases and the distribution of the ?-relaxation times becomes smaller with increase in the annealing time for isothermal annealing. The observed change in the ? process is discussed with respect to the interfacial interaction between the thin layers of stacked thin polymer films.

  18. Glass transition dynamics of stacked thin polymer films.

    PubMed

    Fukao, Koji; Terasawa, Takehide; Oda, Yuto; Nakamura, Kenji; Tahara, Daisuke

    2011-10-01

    The glass transition dynamics of stacked thin films of polystyrene and poly(2-chlorostyrene) were investigated using differential scanning calorimetry and dielectric relaxation spectroscopy. The glass transition temperature T(g) of as-stacked thin polystyrene films has a strong depression from that of the bulk samples. However, after annealing at high temperatures above T(g), the stacked thin films exhibit glass transition at a temperature almost equal to the T(g) of the bulk system. The ?-process dynamics of stacked thin films of poly(2-chlorostyrene) show a time evolution from single-thin-film-like dynamics to bulk-like dynamics during the isothermal annealing process. The relaxation rate of the ? process becomes smaller with increase in the annealing time. The time scale for the evolution of the ? dynamics during the annealing process is very long compared with that for the reptation dynamics. At the same time, the temperature dependence of the relaxation time for the ? process changes from Arrhenius-like to Vogel-Fulcher-Tammann dependence with increase of the annealing time. The fragility index increases and the distribution of the ?-relaxation times becomes smaller with increase in the annealing time for isothermal annealing. The observed change in the ? process is discussed with respect to the interfacial interaction between the thin layers of stacked thin polymer films. PMID:22181166

  19. Submillimeter-wave response of Nb-YBaCuO point-contact Josephson junctions using YBaCuO thin films prepared by CVD

    NASA Astrophysics Data System (ADS)

    Imai, Syozo; Sugawara, Nobuhiro; Sumiya, Kazushige; Ito, Kimihiho; Mikoshiba, Nobuo

    1990-10-01

    The Shapiro steps in the submillimeter wave (SMMW) region were measured in point-contact Josephson junctions made of a Nb strip with a sharpened edge and a YBaCuO thin film. The thin film was prepared by the chemical vapor deposition (CVD) method. The dependence of the Shapiro step width on the SMMW power was measured for the wavelength of 570.6 microns (525.4 GHz). The dependence was similar to that found in microbridges made of low Tc superconductors. The first-order Shapiro step was observed for the wavelength of 232.9 microns (1.287 THz).

  20. Epitaxial growth of high mobility Cu2O thin films and application to p-channel thin film transistor

    Microsoft Academic Search

    Kosuke Matsuzaki; Kenji Nomura; Hiroshi Yanagi; Toshio Kamiya; Masahiro Hirano; Hideo Hosono

    2008-01-01

    Cu2O epitaxial films were grown for high mobility p-channel oxide thin-film transistors (TFTs). The use of a (110) MgO surface and fine tuning of a growth condition produced single phase epitaxial films with hole Hall mobilities ~90 cm2 V-1 s-1 comparable to those of single crystals (~100 cm2 V-1 s-1). TFTs using the epitaxial film channels exhibited p-channel operation although

  1. Substrate Effect on the Melting Temperature of Thin Polyethylene Films M. Rafailovich,1,* J. Sokolov,1

    E-print Network

    Substrate Effect on the Melting Temperature of Thin Polyethylene Films Y. Wang,1 M. Rafailovich,1 polyethylene thin films. The Tm decreases with the film thickness decrease when the film is thinner than that the degree of crystal- linity of polyethylene (PE) remained high even in films as thin as 15 nm [5]. A novel

  2. TI--CR--AL--O thin film resistors

    DOEpatents

    Jankowski, Alan F. (Livermore, CA); Schmid, Anthony P. (Solana Beach, CA)

    2000-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  3. Microstructural Characterization of Thin Polyimide Films by Positron Lifetime Spectroscopy

    NASA Technical Reports Server (NTRS)

    Eftekhari, A.; St.Clair, A. K.; Stoakley, D. M.; Sprinkle, Danny R.; Singh, J. J.

    1996-01-01

    Positron lifetimes have been measured in a series of thin aromatic polyimide films. No evidence of positronium formation was observed in any of the films investigated. All test films exhibited only two positron lifetime components, the longer component corresponding to the positrons annihilating at shallow traps. Based on these trapped positron lifetimes, free volume fractions have been calculated for all the films tested. A free volume model has been developed to calculate the dielectric constants of thin polyimide films. The experimental and the calculated values for the dielectric constants of the films tested are in reasonably good agreement. It has been further noted that the presence of bulky CF(sub 3) groups and meta linkages in the polyimide structure results in higher free volume fraction and, consequently, lower dielectric constant values for the films studied.

  4. Vibrational spectroscopy of organic thin films used for solar cells

    NASA Astrophysics Data System (ADS)

    Furukawa, Yukio

    2013-09-01

    We review infrared and Raman analyses of thin films of organic semiconductors used for active layers in organic solar cells. We present Raman study of blend (bulk heterojunction) films of regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The contents of the crystalline region of P3HT in the blend films prepared by various methods were estimated by Raman spectroscopy. Temperature dependence of photoinduced infrared absorption from a P3HT:PCBM blend film gives the activation energy of the recombination of photoinduced positive and negative carriers. The activation energies for P3HT:PCBM blend films with various PCBM contents were obtained. It has been demonstrated that infrared and Raman spectroscopy is useful for evaluating thin films of P3HT:PCBM blend films used for organic solar cells.

  5. Developing Multilayer Thin Film Strain Sensors With High Thermal Stability

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Gonzalez, Jose M., III

    2006-01-01

    A multilayer thin film strain sensor for large temperature range use is under development using a reactively-sputtered process. The sensor is capable of being fabricated in fine line widths utilizing the sacrificial-layer lift-off process that is used for micro-fabricated noble-metal sensors. Tantalum nitride films were optimized using reactive sputtering with an unbalanced magnetron source. A first approximation model of multilayer resistance and temperature coefficient of resistance was used to set the film thicknesses in the multilayer film sensor. Two multifunctional sensors were fabricated using multilayered films of tantalum nitride and palladium chromium, and tested for low temperature resistivity, TCR and strain response. The low temperature coefficient of resistance of the films will result in improved stability in thin film sensors for low to high temperature use.

  6. Thin film photovoltaic device and process of manufacture

    DOEpatents

    Albright, Scot P. (Lakewood, CO); Chamberlin, Rhodes (El Paso, TX)

    1999-02-09

    Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells.

  7. Thin film photovoltaic device and process of manufacture

    DOEpatents

    Albright, S.P.; Chamberlin, R.

    1999-02-09

    Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells. 13 figs.

  8. Thin film photovoltaic device and process of manufacture

    DOEpatents

    Albright, Scot P. (Lakewood, CO); Chamberlin, Rhodes (El Paso, TX)

    1997-10-07

    Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells.

  9. Thin film photovoltaic device and process of manufacture

    DOEpatents

    Albright, S.P.; Chamberlin, R.

    1997-10-07

    Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells. 13 figs.

  10. A New Optically Reflective Thin Layer Electrode (ORTLE) Window: Gold on a Thin Porous Alumina Film Used to Observe the

    E-print Network

    Myrick, Michael Lenn

    of aluminum thin films sputtered onto an electrically insulating substrate ± a plain float glass microscope of aluminum sputtered onto a plain glass microscope slide to create a 750 nm-thick porous alumina film. A thin

  11. Cracking of thin films: the role of interfaces

    SciTech Connect

    He, M.Y. [Univ. of California, Santa Barbara, CA (United States)

    1996-12-31

    This paper addresses some micromechanics analyses for thin film cracking with emphasis placed on the role of interfaces. Fail-safe bounds are provided through the discussion of four problems related to different failure modes.

  12. Morphology and Surface Areas of Thin Ice Films

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun; Keyser, Leon F.; Timonen, Raimo S.

    1996-01-01

    Thin ice films formed by deposition from the vapor phase in a fast flow-tube reactor have been used to simulate polar stratospheric cloud surfaces in order to obtain laboratory data on uptake and heterogeneous reaction rates.

  13. Combinatorial Characterization of Complex Polymers: Thin Film and Biomedical Polymers

    NSDL National Science Digital Library

    Meredith, J. Carson

    2001-01-01

    Combinatorial methods are presented for assaying thin-film phenomena and cell adhesion and proliferation on biodegradable polymers as a function of composition, thickness, microstructure and topography of polymeric substrates.

  14. The macroscopic delamination of thin films from elastic substrates

    E-print Network

    Reis, Pedro Miguel

    The wrinkling and delamination of stiff thin films adhered to a polymer substrate have important applications in “flexible electronics.” The resulting periodic structures, when used for circuitry, have remarkable mechanical ...

  15. Antimony-Doped Tin(II) Sulfide Thin Films

    E-print Network

    Chakraborty, Rupak

    Thin-film solar cells made from earth-abundant, inexpensive, and nontoxic materials are needed to replace the current technologies whose widespread use is limited by their use of scarce, costly, and toxic elements. Tin ...

  16. Modeling of thin-film solar thermoelectric generators

    E-print Network

    Weinstein, Lee Adragon

    Recent advances in solar thermoelectric generator (STEG) performance have raised their prospect as a potential technology to convert solar energy into electricity. This paper presents an analysis of thin-film STEGs. ...

  17. Enabling integration of vapor-deposited polymer thin films

    E-print Network

    Petruczok, Christy D. (Christy Danielle)

    2014-01-01

    Initiated Chemical Vapor Deposition (iCVD) is a versatile, one-step process for synthesizing conformal and functional polymer thin films on a variety of substrates. This thesis emphasizes the development of tools to further ...

  18. Functionalized multilayer thin films for protection against acutely toxic agents

    E-print Network

    Krogman, Kevin Christopher

    2009-01-01

    The recently developed practice of spraying polyelectrolyte solutions onto a substrate in order to construct thin films via the Layer-by-Layer (LbL) technique has been further investigated and extended. In this process a ...

  19. Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films

    E-print Network

    Yang, You-Hao

    2012-10-19

    Thin films with the ability to impart oxygen and other types of gas barrier are crucial to commercial packaging applications. Commodity polymers, such as polyethylene (PE), polycarbonate (PC) and polyethylene terephthalate (PET), have insufficient...

  20. Structural, magnetic, and optical properties of orthoferrite thin films

    E-print Network

    Supplee, William Wagner

    2007-01-01

    Pulsed laser deposition was used to create thin films of Ce-Fe-O and Y-Fe-O systems. Deposition temperature and ambient oxygen pressure were varied systematically between samples to determine which deposition conditions ...

  1. Preparation of silver-activated zinc sulfide thin films

    NASA Technical Reports Server (NTRS)

    Feldman, C.; Swindells, F. E.

    1968-01-01

    Silver improves luminescence and reduces contamination of zinc sulfide phosphors. The silver is added after the zinc sulfide phosphors are deposited in thin films by vapor evaporation, but before calcining, by immersion in a solution of silver salt.

  2. Shock Dynamics in Particle-Laden Thin Films

    E-print Network

    Dupuy, B.

    2005-04-22

    We present theory and experiments for thin film particle-laden flow on an incline. At higher particle concentration and inclination angle, a new phenomenon is observed in which a large particle-rich ridge forms at the ...

  3. Multimonth controlled small molecule release from biodegradable thin films

    E-print Network

    Hammond, Paula T.

    Long-term, localized delivery of small molecules from a biodegradable thin film is challenging owing to their low molecular weight and poor charge density. Accomplishing highly extended controlled release can facilitate ...

  4. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet that includes scope, core competencies and capabilities, and contact/web information for Polycrystalline Thin-Film Research: Cadmium Telluride at the National Center for Photovoltaics.

  5. A thin film hydroponic system for plant studies

    NASA Technical Reports Server (NTRS)

    Hines, Robert; Prince, Ralph; Muller, Eldon; Schuerger, Andrew

    1990-01-01

    The Land Pavillion, EPCOT Center, houses a hydroponic, thin film growing system identical to that residing in NASA's Biomass Production Chamber at Kennedy Space Center. The system is targeted for plant disease and nutrition studies. The system is described.

  6. Optical and Structural Characterizations of Tin Phthalocvanine Thin Films

    SciTech Connect

    Cherian, Regimol C.; Menon, C. S. [School of Pure and Applied Physics, Mahatma Gandhi University Priyadarshini Hills P.O., Kottayam-686560, Kerala (India)

    2008-04-23

    Phthalocyanines are today regarded as optical materials, which applies to organic dye lasers. The analysis of the optical properties of these thin films enforces the application in the field of thin film optics. Tin phthalocyanine (SnPc) thin films used for the characterization studies are prepared by thermal evaporation technique. The variation of optical band gap with irradiation of heat radiation and post deposition heat treatment are studied from the absorption spectra. Structural properties have been analyzed using the X-ray diffractogram of SnPc powder and thin films. The structure is identified as monoclinic with a = 12.132 A, b = 8.712 A, c = 10.806 A and {beta} = 108.85 deg. The grain size increases with increase of annealing temperature. The SEM images show a rough corrugated surface. Due to heat treatment, crystallites grow into bigger size.

  7. Direct printing of lead zirconate titanate thin films

    E-print Network

    Bathurst, Stephen, 1980-

    2008-01-01

    Thus far, use of lead zirconate titanate (PZT) in MEMS has been limited due to the lack of process compatibility with existing MEMS manufacturing techniques. Direct printing of thin films eliminates the need for photolithographic ...

  8. TiNi-based thin films for MEMS applications

    E-print Network

    Fu, Yongqing

    In this paper, some critical issues and problems in the development of TiNi thin films were discussed, including preparation and characterization considerations, residual stress and adhesion, frequency improvement, fatigue ...

  9. Microfocusing optical device using piezoelectric thin-film actuator

    NASA Astrophysics Data System (ADS)

    Goto, Hiroshi; Wakabayashi, Shyuichi; Ikeda, Masaaki; Sakata, Minoru; Imanaka, Koichi; Takeuchi, Masashi; Yada, Tsuneji

    1995-05-01

    A novel micro focusing optical device controlled by a piezoelectric thin film micro actuator has been presented. This device is provided by bonding two micromachined substrates, which are a glass substrate integrated with a surface emitting light element and a micro Fresnel lens on each surface, and a silicon substrate with a diaphragm type of piezoelectric thin film actuator on it. The surface of the thin film is used as a movable reflection mirror. Focusing is performed by changing position of the mirror surface along the optical axis. In the case of applying the micro lens with 1.3 mm of diameter and 0.33 of N.A. to this focusing device and the thin film actuator capable of several micron displacement, focal point shifting of over 100 mm is obtained. Applying the device to optical senors such as a barcode reader, miniaturization of the light source and high resolution detecting for wide range could be possible.

  10. Properties and sensor performance of zinc oxide thin films

    E-print Network

    Min, Yongki, 1965-

    2003-01-01

    Reactively sputtered ZnO thin film gas sensors were fabricated onto Si wafers. The atmosphere dependent electrical response of the ZnO micro arrays was examined. The effects of processing conditions on the properties and ...

  11. A New Approach for Evaluating Thin Film Interface Fracture Toughness

    SciTech Connect

    Wang, Jy-An John [ORNL; Wright, Ian G [ORNL; Lance, Michael J [ORNL; Liu, Ken C [ORNL

    2006-01-01

    A material configuration of central importance in micro electronics, optoelectronics, and thermal barrier coating technology is a thin film of one material deposited onto a substrate of a different material. Fabrication of such a structure inevitably gives rise to stress in the film due to lattice mismatch, differing coefficient of thermal expansion, chemical reactions, or other physical effects. Therefore, in general, the weakest link in this composite system often resides at the interface between the thin film and substrate. In order to make multi-layered electronic devices and structural composites with long-term reliability, the fracture behavior of the material interfaces must be known. This project is intended to address the problems associated with the deficiency of the existing methods, which show severe scatter in the existing data and the procedure dependence in thin film/coating evaluation methods, and offers an innovative testing procedure for the determination of interface fracture toughness applicable to thin coating materials in general.

  12. Magnetoresistance of bismuth in bulk and thin film forms

    NASA Astrophysics Data System (ADS)

    Dange, S. N.; Saha, Ritwik; Patade, A. M.; Mahadkar, Ajit; Pujara, Deepa T.; Vansutre, S. V.; Radha, S.

    2014-04-01

    A comparative study of the room temperature magnetoresistance (MR) of bulk polycrystalline Bi and its thin film formulations by thermal evaporation is made. The magnetoresistance value for the bulk Bi is found to be positive, reaching a value of 110% in fields of 2T in agreement with the previously reported values. The thermally evaporated thin films of thickness 100 - 300nm show a crystalline nature and the MR values are in the range 3-10%. The resistivity of the thin films shows a semiconducting behavior with a negative temperature coefficient resistance (TCR). Annealing the samples in temperatures of 200°C (below the melting point of pure Bi) is found to cause a reduction in magnetoresistance in thin film samples while there is not much change in the bulk.

  13. Self-Assembling Process for Fabricating Tailored Thin Films

    ScienceCinema

    None

    2010-01-08

    A simple, economical nanotechnology coating process that enables the development of nanoparticle thin films with architectures and properties unattainable by any other processing method. 2007 R&D 100 winner (SAND2007-1878P)

  14. Self-Assembling Process for Fabricating Tailored Thin Films

    ScienceCinema

    Sandia

    2009-09-01

    A simple, economical nanotechnology coating process that enables the development of nanoparticle thin films with architectures and properties unattainable by any other processing method. 2007 R&D 100 winner (SAND2007-1878P)

  15. Surface characterization of plasma-polymerized cyclohexane thin film

    SciTech Connect

    Choi, Changrok; Yeo, Sanghak; Shon, Hyun Kyong; Kim, Jeong Won; Moon, Dae Won; Jung, Donggeun; Lee, Tae Geol [Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); NanoBio Fusion Research Center, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of); Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); NanoBio Fusion Research Center, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of)

    2007-07-15

    A plasma-polymerized cyclohexane (PPCHex) thin film was characterized by using Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry along with a principal component analysis (PCA). The PPCHex thin film was deposited onto a silicon substrate by using an inductively coupled plasma chemical vapor deposition method and cyclohexane as a precursor. The chemical composition of the PPCHex surface was controlled in a reproducible manner as a function of substrate bias plasma power. A PCA of the TOF-SIMS data also gave systematic insight into the surface chemical compositions and molecular cross-linking on plasma-polymerized thin films as a function of substrate bias plasma power. PPCHex thin film made at 100 W plasma power had the least amount of oxygen functional groups such as the C-O-H form on the surface than the one made at 10 W plasma power.

  16. Electrical properties of quench-condensed thin film

    E-print Network

    Lee, Kyoungjin

    2009-05-15

    Electrical properties of thin film have been an issue of interest for a long time and there are many applications in contemporary industry. Interesting characteristics, such as a metal-insulator transition and superconductivity, were investigated...

  17. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    SciTech Connect

    Not Available

    2013-06-01

    This National Center for Photovoltaics sheet describes the capabilities of its polycrystalline thin-film research in the area of cadmium telluride. The scope and core competencies and capabilities are discussed.

  18. PREFACE: Innovations in Thin Film Processing and Characterisation

    NASA Astrophysics Data System (ADS)

    Henrion, Gérard; Belmahi, Mohammed; Andrieu, Stéphane

    2010-07-01

    This special issue contains selected papers which were presented as invited or contributed communications at the 4th International Conference on Innovation in Thin Film Processing and Characterization (ITFPC'09) which was held on 17-20 November, 2009 in Nancy (France) Jointly organized by the French Vacuum Society and the Institut Jean Lamour-a joint research unit specialized in materials, metallurgy, nano-sciences, plasmas and surfaces-the ITFPC conferences aim at providing an open forum to discuss the progress and latest developments in thin film processing and engineering. Invited lectures aim particularly at providing overviews on scientific topics while contributed communications focus on particular cutting-edge aspects of thin film science and technology, including CVD, PVD and ion beam assisted processes. The 2009 conference was organized along the 6 main following topics: Thin films processing and surface engineering Numerical simulation and thin film characterization Protective applications of thin films Energy, environment and health applications of thin films Micro- and nano-patterning of thin films New properties and applications resulting from patterned thin films which were completed by a special half day session devoted to industry-supported innovation. 180 scientists from 20 worldwide countries attended the different sessions along with the 9 invited lectures and 130 contributions were given. Besides the outstanding scientific program, a half-day tutorial session preceded the conference. During the short courses, emphasis was laid on: Lithography for thin film patterning Mechanical properties of thin films Principles and applications of reactive sputtering processes. The French Vacuum Society granted financial aid to PhD students who applied for it in order to encourage the participation of young scientists. The 19 papers published in this volume were accepted for publication after peerreviewal as for regular papers. As chairmen of this conference, we gratefully acknowledge all referees for their valuable work sometimes with a rather short delay. We also express our gratitude to the international members of the scientific committee who actively contributed to ensure an attractive program in proposing invited speakers; it was a difficult task for them to select only 9 out of the large number of proposed recognized experts. Finally, ITFPC'09 would not have been successful without the strong involvement and implication of the local organizing committee and the support of our partners. They will all find here our sincere thanks. Gérard Henrion, Mohammed Belmahi and Stéphane Andrieu Co-chairmen of the ITFPC-09 Conference.

  19. Cratering Studies in Thin Plastic Films

    NASA Astrophysics Data System (ADS)

    Shu, Anthony; Bugiel, S.; Gruen, E.; Horanyi, M.; Munsat, T.; Srama, R.; Colorado CenterLunar Dust; Atmospheric Studies (CCLDAS) Team

    2013-10-01

    Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (? 1000 Å) of aluminum nickel. The operation principle is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theoretical basis for signal interpretation uses a crater diameter scaling law which was not intended for use with PVDF. In this work, a crater size scaling law has been experimentally determined, and further simulation work is being done to enhance our understanding of the mechanisms of crater formation. Two Smoothed Particle Hydrodynamics (SPH) codes are being evaluated for use as a simulator for hypervelocity impacts: Ansys Autodyn and LS-Dyna from the Livermore Software Technology Corp. SPH is known to be well suited to the large deformities found in hypervelocity impacts. It is capable of incorporating key physics phenomena, including fracture, heat transfer, melting, etc. Furthermore, unlike Eulerian methods, SPH is gridless allowing large deformities without the inclusion of unphysical erosion algorithms. Experimental results and preliminary simulation results and conclusions will be presented.

  20. Templated dewetting of thin solid films

    E-print Network

    Giermann, Amanda L. (Amanda Leah)

    2009-01-01

    The dewetting of solid metal polycrystalline films to form metal nanoparticles occurs by the nucleation and growth of holes in the film. For typical films on flat substrates, this process is not well-controlled and results ...